From: Arnaud Lecomte <contact@arnaud-lcm.com> mainline inclusion from mainline-v6.19-rc1 commit 23f852daa4bab4d579110e034e4d513f7d490846 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19054 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Syzkaller reported a KASAN slab-out-of-bounds write in __bpf_get_stackid() when copying stack trace data. The issue occurs when the perf trace contains more stack entries than the stack map bucket can hold, leading to an out-of-bounds write in the bucket's data array. Fixes: ee2a098851bf ("bpf: Adjust BPF stack helper functions to accommodate skip > 0") Reported-by: syzbot+c9b724fbb41cf2538b7b@syzkaller.appspotmail.com Signed-off-by: Arnaud Lecomte <contact@arnaud-lcm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/bpf/20251025192941.1500-1-contact@arnaud-lcm.com Closes: https://syzkaller.appspot.com/bug?extid=c9b724fbb41cf2538b7b Conflicts: kernel/bpf/stackmap.c [Make variable nr definition up to avoid build warning] Signed-off-by: Pu Lehui <pulehui@huawei.com> --- kernel/bpf/stackmap.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 7b1a4bd79efe..9ff3e5af8da2 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -430,8 +430,8 @@ static long __bpf_get_stackid(struct bpf_map *map, { struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); struct stack_map_bucket *bucket, *new_bucket, *old_bucket; + u32 hash, id, trace_nr, trace_len, max_depth; u32 skip = flags & BPF_F_SKIP_FIELD_MASK; - u32 hash, id, trace_nr, trace_len; bool user = flags & BPF_F_USER_STACK; u64 *ips; bool hash_matches; @@ -440,7 +440,8 @@ static long __bpf_get_stackid(struct bpf_map *map, /* skipping more than usable stack trace */ return -EFAULT; - trace_nr = trace->nr - skip; + max_depth = stack_map_calculate_max_depth(map->value_size, stack_map_data_size(map), flags); + trace_nr = min_t(u32, trace->nr - skip, max_depth - skip); trace_len = trace_nr * sizeof(u64); ips = trace->ip + skip; hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); @@ -546,7 +547,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, struct perf_event *event = ctx->event; struct perf_callchain_entry *trace; bool kernel, user; - __u64 nr_kernel; + __u64 nr_kernel, nr; int ret; /* perf_sample_data doesn't have callchain, use bpf_get_stackid */ @@ -566,15 +567,11 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, return -EFAULT; nr_kernel = count_kernel_ip(trace); + nr = trace->nr; /* save original */ if (kernel) { - __u64 nr = trace->nr; - trace->nr = nr_kernel; ret = __bpf_get_stackid(map, trace, flags); - - /* restore nr */ - trace->nr = nr; } else { /* user */ u64 skip = flags & BPF_F_SKIP_FIELD_MASK; @@ -585,6 +582,10 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; ret = __bpf_get_stackid(map, trace, flags); } + + /* restore nr */ + trace->nr = nr; + return ret; } -- 2.34.1