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[PATCH OLK-5.10] bpf: Disable preemption in __bpf_get_stack
by Pu Lehui 17 Sep '26

17 Sep '26

From: Daniel Borkmann <borkmann(a)iogearbox.net> mainline inclusion from mainline-v7.3-rc1 commit b1a47b2708d4e95dbd23aee2ec83752190897b3f category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18901 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- get_perf_callchain() returns a per-CPU perf_callchain_entry buffer and releases its recursion slot via put_callchain_entry() before returning, so nothing keeps the entry reserved while __bpf_get_stack() consumes it below. A preemptible BPF program (e.g. a non-sleepable raw tracepoint program on a PREEMPT kernel, which runs under migrate_disable() but not preempt_disable()) can be scheduled out between obtaining the entry and the copy. Another task scheduled on the same CPU then reuses the same per-CPU buffer and overwrites trace->nr with a larger value. copy_len is then computed from the inflated trace->nr and can exceed the caller's buffer, causing an out-of-bounds write in the memcpy() and in the build_id path. The rcu_read_lock() taken here alone does not prevent this. It is only taken on the may_fault path, and under CONFIG_PREEMPT_RCU it does not disable preemption; it merely keeps perf's callchain buffer array alive (freed via call_rcu()) and does nothing to stop another task from reusing the entry. Disable preemption around obtaining the callchain entry and copying it into the caller's buffer, so the entry cannot be reused underneath us and trace->nr stays bounded by max_depth. Build ID resolution may fault and is therefore deferred until after preemption is re-enabled; by then the instruction pointers have already been copied into buf, so it operates only on that private copy. Note, preempt_disable() also subsumes the buffer-lifetime guarantee the rcu_read_lock() provided, since a preempt-disabled section is an RCU read-side critical section for the callchain buffers' call_rcu() reclaim. Fixes: c195651e565a ("bpf: add bpf_get_stack helper") Reported-by: Tao Chen <chen.dylane(a)linux.dev> Reported-by: STAR Labs SG <info(a)starlabs.sg> Signed-off-by: Daniel Borkmann <borkmann(a)iogearbox.net> Signed-off-by: Jiri Olsa <jolsa(a)kernel.org> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/bpf/20260803210149.296496-11-jolsa@kernel.org Closes: https://lore.kernel.org/bpf/20260206090653.1336687-1-chen.dylane@linux.dev/ [ changed Fixes: commit ] Conflicts: kernel/bpf/stackmap.c [not refactor to callchain_store and callchain_finalize] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/bpf/stackmap.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 0c3504e598e3..1f2547acf3d1 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -620,6 +620,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, if (sysctl_perf_event_max_stack < max_depth) max_depth = sysctl_perf_event_max_stack; + preempt_disable(); if (trace_in) trace = trace_in; else if (kernel && task) @@ -627,16 +628,22 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, else trace = get_perf_callchain(regs, 0, kernel, user, max_depth, crosstask, false); - if (unlikely(!trace)) + if (unlikely(!trace)) { + preempt_enable(); goto err_fault; + } - if (trace->nr < skip) + if (trace->nr < skip) { + preempt_enable(); goto err_fault; + } trace_nr = trace->nr - skip; trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; copy_len = trace_nr * elem_size; + preempt_enable(); + ips = trace->ip + skip; if (user && user_build_id) stack_map_get_build_id_offset(buf, ips, trace_nr, user); -- 2.34.1

1 0

[PATCH OLK-6.6] bpf: Disable preemption in __bpf_get_stack
by Pu Lehui 17 Sep '26

17 Sep '26

From: Daniel Borkmann <borkmann(a)iogearbox.net> mainline inclusion from mainline-v7.3-rc1 commit b1a47b2708d4e95dbd23aee2ec83752190897b3f category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18901 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- get_perf_callchain() returns a per-CPU perf_callchain_entry buffer and releases its recursion slot via put_callchain_entry() before returning, so nothing keeps the entry reserved while __bpf_get_stack() consumes it below. A preemptible BPF program (e.g. a non-sleepable raw tracepoint program on a PREEMPT kernel, which runs under migrate_disable() but not preempt_disable()) can be scheduled out between obtaining the entry and the copy. Another task scheduled on the same CPU then reuses the same per-CPU buffer and overwrites trace->nr with a larger value. copy_len is then computed from the inflated trace->nr and can exceed the caller's buffer, causing an out-of-bounds write in the memcpy() and in the build_id path. The rcu_read_lock() taken here alone does not prevent this. It is only taken on the may_fault path, and under CONFIG_PREEMPT_RCU it does not disable preemption; it merely keeps perf's callchain buffer array alive (freed via call_rcu()) and does nothing to stop another task from reusing the entry. Disable preemption around obtaining the callchain entry and copying it into the caller's buffer, so the entry cannot be reused underneath us and trace->nr stays bounded by max_depth. Build ID resolution may fault and is therefore deferred until after preemption is re-enabled; by then the instruction pointers have already been copied into buf, so it operates only on that private copy. Note, preempt_disable() also subsumes the buffer-lifetime guarantee the rcu_read_lock() provided, since a preempt-disabled section is an RCU read-side critical section for the callchain buffers' call_rcu() reclaim. Fixes: c195651e565a ("bpf: add bpf_get_stack helper") Reported-by: Tao Chen <chen.dylane(a)linux.dev> Reported-by: STAR Labs SG <info(a)starlabs.sg> Signed-off-by: Daniel Borkmann <borkmann(a)iogearbox.net> Signed-off-by: Jiri Olsa <jolsa(a)kernel.org> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/bpf/20260803210149.296496-11-jolsa@kernel.org Closes: https://lore.kernel.org/bpf/20260206090653.1336687-1-chen.dylane@linux.dev/ [ changed Fixes: commit ] Conflicts: kernel/bpf/stackmap.c [not refactor to callchain_store and callchain_finalize] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/bpf/stackmap.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 2a4070d0b594..a30a136ea954 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -444,6 +444,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, max_depth = stack_map_calculate_max_depth(size, elem_size, flags); + preempt_disable(); if (trace_in) { trace = trace_in; trace->nr = min_t(u32, trace->nr, max_depth); @@ -453,15 +454,21 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, trace = get_perf_callchain(regs, 0, kernel, user, max_depth, crosstask, false); } - if (unlikely(!trace)) + if (unlikely(!trace)) { + preempt_enable(); goto err_fault; + } - if (trace->nr < skip) + if (trace->nr < skip) { + preempt_enable(); goto err_fault; + } trace_nr = trace->nr - skip; copy_len = trace_nr * elem_size; + preempt_enable(); + ips = trace->ip + skip; if (user && user_build_id) stack_map_get_build_id_offset(buf, ips, trace_nr, user); -- 2.34.1

1 0

[PATCH OLK-5.10] ceph: bound num_export_targets array for mds info v2/v3
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> mainline inclusion from mainline-v7.3-rc1 commit a3eb169ee297aa99670ba927c659990bd1e453f3 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19003 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- ceph_mdsmap_decode() in fs/ceph/mdsmap.c reads num_export_targets from each per-mds info record and advances the decode cursor by num_export_targets * sizeof(u32) without first checking that many bytes remain. The only upper-bound check that catches a runaway cursor (*p > info_end) is gated on info_v >= 4, because info_end is left NULL for info_v 2 and 3. When the monitor sends an MDS map whose per-mds info version is 2 or 3 with an oversized num_export_targets, the cursor moves past the message front buffer and the later export-targets loop calls the unchecked ceph_decode_32() on out-of-bounds memory. A kernel client processes CEPH_MSG_MDS_MAP from its monitor session (net/ceph/mon_client.c dispatches it; fs/ceph/super.c routes it to ceph_mdsc_handle_mdsmap(), which sets end to the front buffer bound and calls ceph_mdsmap_decode()). A malicious or compromised monitor, or an on-path attacker on an unsigned/unencrypted messenger session, can therefore drive an out-of-bounds read in the client kernel; on x86_64 with KASAN it is reported as a slab-out-of-bounds read in ceph_mdsmap_decode(). The decoded values land in the internal info->export_targets[] array, so the consequence is a kernel out-of-bounds read, not an information leak to the attacker. Impact: a malicious or compromised Ceph monitor sending an MDS map with a per-mds info version of 2 or 3 and an oversized num_export_targets field triggers an out-of-bounds read in the CephFS client kernel. Add a ceph_decode_need() for the export-targets array before advancing the cursor, so the bound is enforced for every info_v >= 2, not only info_v >= 4. This mirrors the count-then-need idiom already used for m_data_pg_pools later in the same function. Compute the export-targets byte count with size_mul() and reuse that checked length when advancing the cursor, so the attacker-controlled num_export_targets multiplication fails closed on overflow rather than relying on the later kcalloc() guard. Cc: stable(a)vger.kernel.org Fixes: d463a43d69f4 ("ceph: CEPH_FEATURE_MDSENC support") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <slava(a)dubeyko.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Conflicts: fs/ceph/mdsmap.c [ctx conflicts] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/mdsmap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index 47f2903bacb9..05c25f1de6ad 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -3,6 +3,7 @@ #include <linux/bug.h> #include <linux/err.h> +#include <linux/overflow.h> #include <linux/random.h> #include <linux/slab.h> #include <linux/types.h> @@ -122,6 +123,7 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end) int err; u8 mdsmap_v; u16 mdsmap_ev; + size_t export_targets_len; m = kzalloc(sizeof(*m), GFP_NOFS); if (!m) @@ -219,8 +221,11 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end) *p += namelen; if (info_v >= 2) { ceph_decode_32_safe(p, end, num_export_targets, bad); + export_targets_len = size_mul(num_export_targets, + sizeof(u32)); + ceph_decode_need(p, end, export_targets_len, bad); pexport_targets = *p; - *p += num_export_targets * sizeof(u32); + *p += export_targets_len; } else { num_export_targets = 0; } -- 2.34.1

2 1

[PATCH OLK-6.6] bpf: Harden bloom filter sizing and indexing on 32-bit kernels
by Pu Lehui 17 Sep '26

17 Sep '26

From: Jérémy Jean <Jeremy.Jean(a)oss.cyber.gouv.fr> stable inclusion from stable-v6.6.157 commit 80551bf8912c42d1e3d55eec6fa3c40f306c3de8 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18900 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 11c1e836710dcba03e50454a4eedfdbaf8d3050e upstream. bloom_map_alloc() has two 32-bit-specific problems when the computed bitmap reaches the U32_MAX fallback case. First, BITS_TO_BYTES(U32_MAX) is evaluated with 32-bit arithmetic. The addition performed by DIV_ROUND_UP wraps, so the map allocates only the fixed-size bloom filter object while keeping bitset_mask == U32_MAX. Subsequent updates can then write past the allocated object. Second, fixing only the allocation size is not sufficient. The bloom hash is a u32, but set_bit() takes a signed long bit number and x86 test_bit() eventually feeds the index to variable_test_bit(long, ...). On 32-bit kernels, hashes in [0x80000000, U32_MAX] therefore become negative bit offsets. x86 bt/bts with a memory operand interpret those offsets relative to the supplied base, so a map with bitset_mask == U32_MAX can read or write before bloom->bitset even after allocating the full 512 MiB bitmap. Keep the U32_MAX fallback, but split each hash into a word pointer and an in-word bit number before calling test_bit() or set_bit(). The bitops argument is then always in [0, BITS_PER_LONG - 1], while BIT_WORD(h) still selects the intended word in the full bitmap. Compute the bitset size from (u64)bitset_mask + 1 before passing the final size to bpf_map_area_alloc(). This fixes the original under-allocation and keeps the allocated storage consistent with the addressable bitset. Exploitation note: local privilege escalation is possible on a 32-bit x86 kernel using the under-allocation bug from a binary with CAP_BPF. Fixes: 9330986c0300 ("bpf: Add bloom filter map implementation") Signed-off-by: Jérémy Jean <Jeremy.Jean(a)oss.cyber.gouv.fr> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/bpf/20260805060228.2703051-1-Jeremy.Jean@oss.cyber.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Assisted-by: Codex:gpt-5 Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- kernel/bpf/bloom_filter.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/kernel/bpf/bloom_filter.c b/kernel/bpf/bloom_filter.c index 35e1ddca74d2..3f55f28fd589 100644 --- a/kernel/bpf/bloom_filter.c +++ b/kernel/bpf/bloom_filter.c @@ -41,7 +41,7 @@ static long bloom_map_peek_elem(struct bpf_map *map, void *value) for (i = 0; i < bloom->nr_hash_funcs; i++) { h = hash(bloom, value, map->value_size, i); - if (!test_bit(h, bloom->bitset)) + if (!test_bit(h % BITS_PER_LONG, bloom->bitset + BIT_WORD(h))) return -ENOENT; } @@ -57,9 +57,13 @@ static long bloom_map_push_elem(struct bpf_map *map, void *value, u64 flags) if (flags != BPF_ANY) return -EINVAL; + /* + * On 32-bit architectures, hashes larger than INT_MAX would be + * treated as negative by set_bit(). + */ for (i = 0; i < bloom->nr_hash_funcs; i++) { h = hash(bloom, value, map->value_size, i); - set_bit(h, bloom->bitset); + set_bit(h % BITS_PER_LONG, bloom->bitset + BIT_WORD(h)); } return 0; @@ -94,9 +98,10 @@ static int bloom_map_alloc_check(union bpf_attr *attr) static struct bpf_map *bloom_map_alloc(union bpf_attr *attr) { - u32 bitset_bytes, bitset_mask, nr_hash_funcs, nr_bits; + u32 bitset_mask, nr_hash_funcs, nr_bits; int numa_node = bpf_map_attr_numa_node(attr); struct bpf_bloom_filter *bloom; + u64 bitset_bytes; if (attr->key_size != 0 || attr->value_size == 0 || attr->max_entries == 0 || @@ -127,22 +132,16 @@ static struct bpf_map *bloom_map_alloc(union bpf_attr *attr) if (check_mul_overflow(attr->max_entries, nr_hash_funcs, &nr_bits) || check_mul_overflow(nr_bits / 5, (u32)7, &nr_bits) || nr_bits > (1UL << 31)) { - /* The bit array size is 2^32 bits but to avoid overflowing the - * u32, we use U32_MAX, which will round up to the equivalent - * number of bytes - */ - bitset_bytes = BITS_TO_BYTES(U32_MAX); bitset_mask = U32_MAX; } else { if (nr_bits <= BITS_PER_LONG) nr_bits = BITS_PER_LONG; else nr_bits = roundup_pow_of_two(nr_bits); - bitset_bytes = BITS_TO_BYTES(nr_bits); bitset_mask = nr_bits - 1; } - bitset_bytes = roundup(bitset_bytes, sizeof(unsigned long)); + bitset_bytes = BITS_TO_LONGS((u64)bitset_mask + 1) * sizeof(unsigned long); bloom = bpf_map_area_alloc(sizeof(*bloom) + bitset_bytes, numa_node); if (!bloom) -- 2.34.1

1 0

[PATCH OLK-6.6] ceph: bound num_export_targets array for mds info v2/v3
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> stable inclusion from stable-v6.6.157 commit eb3e1a1cb1634c76d59c5a9cb1a026fc69d40911 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19003 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit a3eb169ee297aa99670ba927c659990bd1e453f3 upstream. ceph_mdsmap_decode() in fs/ceph/mdsmap.c reads num_export_targets from each per-mds info record and advances the decode cursor by num_export_targets * sizeof(u32) without first checking that many bytes remain. The only upper-bound check that catches a runaway cursor (*p > info_end) is gated on info_v >= 4, because info_end is left NULL for info_v 2 and 3. When the monitor sends an MDS map whose per-mds info version is 2 or 3 with an oversized num_export_targets, the cursor moves past the message front buffer and the later export-targets loop calls the unchecked ceph_decode_32() on out-of-bounds memory. A kernel client processes CEPH_MSG_MDS_MAP from its monitor session (net/ceph/mon_client.c dispatches it; fs/ceph/super.c routes it to ceph_mdsc_handle_mdsmap(), which sets end to the front buffer bound and calls ceph_mdsmap_decode()). A malicious or compromised monitor, or an on-path attacker on an unsigned/unencrypted messenger session, can therefore drive an out-of-bounds read in the client kernel; on x86_64 with KASAN it is reported as a slab-out-of-bounds read in ceph_mdsmap_decode(). The decoded values land in the internal info->export_targets[] array, so the consequence is a kernel out-of-bounds read, not an information leak to the attacker. Impact: a malicious or compromised Ceph monitor sending an MDS map with a per-mds info version of 2 or 3 and an oversized num_export_targets field triggers an out-of-bounds read in the CephFS client kernel. Add a ceph_decode_need() for the export-targets array before advancing the cursor, so the bound is enforced for every info_v >= 2, not only info_v >= 4. This mirrors the count-then-need idiom already used for m_data_pg_pools later in the same function. Compute the export-targets byte count with size_mul() and reuse that checked length when advancing the cursor, so the attacker-controlled num_export_targets multiplication fails closed on overflow rather than relying on the later kcalloc() guard. Cc: stable(a)vger.kernel.org Fixes: d463a43d69f4 ("ceph: CEPH_FEATURE_MDSENC support") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <slava(a)dubeyko.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/mdsmap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index c046b567ac30..939790d2620f 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -3,6 +3,7 @@ #include <linux/bug.h> #include <linux/err.h> +#include <linux/overflow.h> #include <linux/random.h> #include <linux/slab.h> #include <linux/types.h> @@ -124,6 +125,7 @@ struct ceph_mdsmap *ceph_mdsmap_decode(struct ceph_mds_client *mdsc, void **p, u8 mdsmap_v; u16 mdsmap_ev; u32 target; + size_t export_targets_len; m = kzalloc(sizeof(*m), GFP_NOFS); if (!m) @@ -222,8 +224,11 @@ struct ceph_mdsmap *ceph_mdsmap_decode(struct ceph_mds_client *mdsc, void **p, *p += namelen; if (info_v >= 2) { ceph_decode_32_safe(p, end, num_export_targets, bad); + export_targets_len = size_mul(num_export_targets, + sizeof(u32)); + ceph_decode_need(p, end, export_targets_len, bad); pexport_targets = *p; - *p += num_export_targets * sizeof(u32); + *p += export_targets_len; } else { num_export_targets = 0; } -- 2.34.1

2 1

[PATCH OLK-6.6] ceph: reject export_targets ranks >= CEPH_MAX_MDS in mdsmap decode
by Pu Lehui 17 Sep '26

17 Sep '26

From: Jérémy Jean <Jeremy.Jean(a)oss.cyber.gouv.fr> stable inclusion from stable-v6.6.157 commit c4addccd05bacbef2144b4db14853d0308a218ac category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18981 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit aedc9053d909508a5f56c3f49f885fc030df4730 upstream. MDSMap export_targets entries are monitor controlled. check_new_map() uses each entry as a bit number in a fixed stack bitmap, so a rank outside the protocol namespace can make set_bit() write past the end of the array. Reject ranks outside CEPH_MAX_MDS while decoding the map. Do not validate against possible_max_rank here because maps may legitimately reference ranks beyond a temporarily reduced max_mds. Cc: stable(a)vger.kernel.org Fixes: d517b3983dd3 ("ceph: reconnect to the export targets on new mdsmaps") Signed-off-by: Jérémy Jean <Jeremy.Jean(a)oss.cyber.gouv.fr> Reviewed-by: Alex Markuze <amarkuze(a)redhat.com> Signed-off-by: Alex Markuze <amarkuze(a)redhat.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/mdsmap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index 15243241bc2b..c046b567ac30 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -264,6 +264,10 @@ struct ceph_mdsmap *ceph_mdsmap_decode(struct ceph_mds_client *mdsc, void **p, goto nomem; for (j = 0; j < num_export_targets; j++) { target = ceph_decode_32(&pexport_targets); + if (target >= CEPH_MAX_MDS) { + err = -EIO; + goto corrupt; + } info->export_targets[j] = target; } } else { -- 2.34.1

2 1

[PATCH openEuler-1.0-LTS] ceph: bound xattr value length in __build_xattrs()
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> mainline inclusion from mainline-v7.3-rc1 commit 68d541754d6cd3bb98d1fd8314f57e5eb533557d category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18970 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- __build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob. For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob. The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space. Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_need() so an out-of-bounds value length on the final attribute fails the decode and returns -EIO instead of being stored. Cc: stable(a)vger.kernel.org Fixes: 355da1eb7a1f ("ceph: inode operations") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko(a)ibm.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/xattr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 5e4f3f833e85..f22811d4ba06 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -685,6 +685,7 @@ static int __build_xattrs(struct inode *inode) name = p; p += len; ceph_decode_32_safe(&p, end, len, bad); + ceph_decode_need(&p, end, len, bad); val = p; p += len; -- 2.34.1

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[PATCH OLK-5.10] ceph: bound xattr value length in __build_xattrs()
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> stable inclusion from stable-v5.10.270 commit 848b80ca6b410f350d08b8ac19a00ef88223f2ea category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18970 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 68d541754d6cd3bb98d1fd8314f57e5eb533557d upstream. __build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob. For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob. The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space. Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_need() so an out-of-bounds value length on the final attribute fails the decode and returns -EIO instead of being stored. Cc: stable(a)vger.kernel.org Fixes: 355da1eb7a1f ("ceph: inode operations") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko(a)ibm.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/xattr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index d1fd81b1b541..80f39d46f12d 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -715,6 +715,7 @@ static int __build_xattrs(struct inode *inode) name = p; p += len; ceph_decode_32_safe(&p, end, len, bad); + ceph_decode_need(&p, end, len, bad); val = p; p += len; -- 2.34.1

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[PATCH OLK-6.6] ceph: bound xattr value length in __build_xattrs()
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> stable inclusion from stable-v6.6.157 commit 61f085cb8976c9cebc90e1a8933e4cc1ad8b0fce category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18970 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- commit 68d541754d6cd3bb98d1fd8314f57e5eb533557d upstream. __build_xattrs() decodes the MDS-supplied xattr blob one attribute at a time. For each attribute it reads a 32-bit name length, advances past the name bytes, reads a 32-bit value length, records the value pointer, and advances past the value bytes. The two length fields are read with ceph_decode_32_safe(), but the value bytes themselves are advanced over with a bare "p += len" and no ceph_decode_need() check that "len" bytes remain in the blob. For every attribute except the last, the next iteration's ceph_decode_32_safe() on the following name length implicitly verifies that the previous value did not run past the blob end. The final attribute has no successor, so its decoded value length is never checked against the blob bounds. A malicious or compromised metadata server can set the last attribute's value length larger than the bytes actually present in the blob. The blob is a dedicated kvmalloc() allocation sized to the wire length (ceph_buffer_new() in ceph_fill_inode()). __set_xattr() records the oversized length in xattr->val_len verbatim, and a later getxattr(2) runs memcpy(value, xattr->val, xattr->val_len) into a user-supplied buffer, copying bytes past the end of the allocation back to user space. Impact: a malicious metadata server discloses adjacent kernel heap bytes to a local user via getxattr(2) on a CephFS file. Add the missing ceph_decode_need() so an out-of-bounds value length on the final attribute fails the decode and returns -EIO instead of being stored. Cc: stable(a)vger.kernel.org Fixes: 355da1eb7a1f ("ceph: inode operations") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko(a)ibm.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/xattr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index 3920aa4e40a8..4abed75b01ba 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -844,6 +844,7 @@ static int __build_xattrs(struct inode *inode) name = p; p += len; ceph_decode_32_safe(&p, end, len, bad); + ceph_decode_need(&p, end, len, bad); val = p; p += len; -- 2.34.1

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[PATCH openEuler-1.0-LTS] ceph: bound num_export_targets array for mds info v2/v3
by Pu Lehui 17 Sep '26

17 Sep '26

From: Michael Bommarito <michael.bommarito(a)gmail.com> mainline inclusion from mainline-v7.3-rc1 commit a3eb169ee297aa99670ba927c659990bd1e453f3 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19003 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… -------------------------------- ceph_mdsmap_decode() in fs/ceph/mdsmap.c reads num_export_targets from each per-mds info record and advances the decode cursor by num_export_targets * sizeof(u32) without first checking that many bytes remain. The only upper-bound check that catches a runaway cursor (*p > info_end) is gated on info_v >= 4, because info_end is left NULL for info_v 2 and 3. When the monitor sends an MDS map whose per-mds info version is 2 or 3 with an oversized num_export_targets, the cursor moves past the message front buffer and the later export-targets loop calls the unchecked ceph_decode_32() on out-of-bounds memory. A kernel client processes CEPH_MSG_MDS_MAP from its monitor session (net/ceph/mon_client.c dispatches it; fs/ceph/super.c routes it to ceph_mdsc_handle_mdsmap(), which sets end to the front buffer bound and calls ceph_mdsmap_decode()). A malicious or compromised monitor, or an on-path attacker on an unsigned/unencrypted messenger session, can therefore drive an out-of-bounds read in the client kernel; on x86_64 with KASAN it is reported as a slab-out-of-bounds read in ceph_mdsmap_decode(). The decoded values land in the internal info->export_targets[] array, so the consequence is a kernel out-of-bounds read, not an information leak to the attacker. Impact: a malicious or compromised Ceph monitor sending an MDS map with a per-mds info version of 2 or 3 and an oversized num_export_targets field triggers an out-of-bounds read in the CephFS client kernel. Add a ceph_decode_need() for the export-targets array before advancing the cursor, so the bound is enforced for every info_v >= 2, not only info_v >= 4. This mirrors the count-then-need idiom already used for m_data_pg_pools later in the same function. Compute the export-targets byte count with size_mul() and reuse that checked length when advancing the cursor, so the attacker-controlled num_export_targets multiplication fails closed on overflow rather than relying on the later kcalloc() guard. Cc: stable(a)vger.kernel.org Fixes: d463a43d69f4 ("ceph: CEPH_FEATURE_MDSENC support") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito(a)gmail.com> Reviewed-by: Viacheslav Dubeyko <slava(a)dubeyko.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> Conflicts: fs/ceph/mdsmap.c [ctx conflicts] Signed-off-by: Pu Lehui <pulehui(a)huawei.com> --- fs/ceph/mdsmap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c index 44e53abeb32a..5583f5e171af 100644 --- a/fs/ceph/mdsmap.c +++ b/fs/ceph/mdsmap.c @@ -3,6 +3,7 @@ #include <linux/bug.h> #include <linux/err.h> +#include <linux/overflow.h> #include <linux/random.h> #include <linux/slab.h> #include <linux/types.h> @@ -111,6 +112,7 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end) int err = -EINVAL; u8 mdsmap_v, mdsmap_cv; u16 mdsmap_ev; + size_t export_targets_len; m = kzalloc(sizeof(*m), GFP_NOFS); if (!m) @@ -192,8 +194,11 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end) *p += namelen; if (info_v >= 2) { ceph_decode_32_safe(p, end, num_export_targets, bad); + export_targets_len = size_mul(num_export_targets, + sizeof(u32)); + ceph_decode_need(p, end, export_targets_len, bad); pexport_targets = *p; - *p += num_export_targets * sizeof(u32); + *p += export_targets_len; } else { num_export_targets = 0; } -- 2.34.1

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