Thadeu Lima de Souza Cascardo (4): ext4: ext4_search_dir should return a proper error ext4: return error on ext4_find_inline_entry ext4: explicitly exit when ext4_find_inline_entry returns an error ext4: avoid OOB when system.data xattr changes underneath the filesystem
fs/ext4/inline.c | 35 +++++++++++++++++++++++++---------- fs/ext4/namei.c | 14 ++++++++------ 2 files changed, 33 insertions(+), 16 deletions(-)
From: Thadeu Lima de Souza Cascardo cascardo@igalia.com
mainline inclusion from mainline-v6.12-rc1 commit cd69f8f9de280e331c9e6ff689ced0a688a9ce8f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPK6 CVE: CVE-2024-47701
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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ext4_search_dir currently returns -1 in case of a failure, while it returns 0 when the name is not found. In such failure cases, it should return an error code instead.
This becomes even more important when ext4_find_inline_entry returns an error code as well in the next commit.
-EFSCORRUPTED seems appropriate as such error code as these failures would be caused by unexpected record lengths and is in line with other instances of ext4_check_dir_entry failures.
In the case of ext4_dx_find_entry, the current use of ERR_BAD_DX_DIR was left as is to reduce the risk of regressions.
Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@igalia.com Link: https://patch.msgid.link/20240821152324.3621860-2-cascardo@igalia.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/ext4/namei.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 0acf6ea7b64f..a4d8f314656c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1448,7 +1448,7 @@ static inline bool ext4_match(const struct inode *parent, }
/* - * Returns 0 if not found, -1 on failure, and 1 on success + * Returns 0 if not found, -EFSCORRUPTED on failure, and 1 on success */ int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size, struct inode *dir, struct ext4_filename *fname, @@ -1469,7 +1469,7 @@ int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size, * a full check */ if (ext4_check_dir_entry(dir, NULL, de, bh, search_buf, buf_size, offset)) - return -1; + return -EFSCORRUPTED; *res_dir = de; return 1; } @@ -1477,7 +1477,7 @@ int ext4_search_dir(struct buffer_head *bh, char *search_buf, int buf_size, de_len = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize); if (de_len <= 0) - return -1; + return -EFSCORRUPTED; offset += de_len; de = (struct ext4_dir_entry_2 *) ((char *) de + de_len); } @@ -1629,8 +1629,10 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir, goto cleanup_and_exit; } else { brelse(bh); - if (i < 0) + if (i < 0) { + ret = ERR_PTR(i); goto cleanup_and_exit; + } } next: if (++block >= nblocks) @@ -1724,7 +1726,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir, if (retval == 1) goto success; brelse(bh); - if (retval == -1) { + if (retval < 0) { bh = ERR_PTR(ERR_BAD_DX_DIR); goto errout; }
From: Thadeu Lima de Souza Cascardo cascardo@igalia.com
stable inclusion from stable-v5.10.227 commit e65f698736b053afac80ce6873f2548170cbae0d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPK6 CVE: CVE-2024-47701
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
[ Upstream commit 4d231b91a944f3cab355fce65af5871fb5d7735b ]
In case of errors when reading an inode from disk or traversing inline directory entries, return an error-encoded ERR_PTR instead of returning NULL. ext4_find_inline_entry only caller, __ext4_find_entry already returns such encoded errors.
Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@igalia.com Link: https://patch.msgid.link/20240821152324.3621860-3-cascardo@igalia.com Signed-off-by: Theodore Ts'o tytso@mit.edu Stable-dep-of: c6b72f5d82b1 ("ext4: avoid OOB when system.data xattr changes underneath the filesystem") Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/ext4/inline.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index 436e09113c9f..a4128047e63f 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -1659,8 +1659,9 @@ struct buffer_head *ext4_find_inline_entry(struct inode *dir, void *inline_start; int inline_size;
- if (ext4_get_inode_loc(dir, &iloc)) - return NULL; + ret = ext4_get_inode_loc(dir, &iloc); + if (ret) + return ERR_PTR(ret);
down_read(&EXT4_I(dir)->xattr_sem); if (!ext4_has_inline_data(dir)) { @@ -1691,7 +1692,10 @@ struct buffer_head *ext4_find_inline_entry(struct inode *dir,
out: brelse(iloc.bh); - iloc.bh = NULL; + if (ret < 0) + iloc.bh = ERR_PTR(ret); + else + iloc.bh = NULL; out_find: up_read(&EXT4_I(dir)->xattr_sem); return iloc.bh;
From: Thadeu Lima de Souza Cascardo cascardo@igalia.com
mainline inclusion from mainline-v6.12-rc1 commit 51e14e78b5fb3e6f839393cd2d34386ee7b69af3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPK6 CVE: CVE-2024-47701
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
__ext4_find_entry currently ignores the return of ext4_find_inline_entry, except for returning the bh or NULL when has_inline_data is 1.
Even though has_inline_data is set to 1 before calling ext4_find_inline_entry and would only be set to 0 when that function returns NULL, check for an encoded error return explicitly in order to exit.
That makes the code more readable, not requiring that one assumes the cases when has_inline_data is 1.
Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@igalia.com Link: https://patch.msgid.link/20240821152324.3621860-4-cascardo@igalia.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/ext4/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a4d8f314656c..13be57a67b8f 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1540,7 +1540,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir, &has_inline_data); if (inlined) *inlined = has_inline_data; - if (has_inline_data) + if (has_inline_data || IS_ERR(ret)) goto cleanup_and_exit; }
From: Thadeu Lima de Souza Cascardo cascardo@igalia.com
stable inclusion from stable-v5.10.227 commit 7fc22c3b3ffc0e952f5e0062dd11aa6ae76affba category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAYPK6 CVE: CVE-2024-47701
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit c6b72f5d82b1017bad80f9ebf502832fc321d796 ]
When looking up for an entry in an inlined directory, if e_value_offs is changed underneath the filesystem by some change in the block device, it will lead to an out-of-bounds access that KASAN detects as an UAF.
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none. loop0: detected capacity change from 2048 to 2047 ================================================================== BUG: KASAN: use-after-free in ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500 Read of size 1 at addr ffff88803e91130f by task syz-executor269/5103
CPU: 0 UID: 0 PID: 5103 Comm: syz-executor269 Not tainted 6.11.0-rc4-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500 ext4_find_inline_entry+0x4be/0x5e0 fs/ext4/inline.c:1697 __ext4_find_entry+0x2b4/0x1b30 fs/ext4/namei.c:1573 ext4_lookup_entry fs/ext4/namei.c:1727 [inline] ext4_lookup+0x15f/0x750 fs/ext4/namei.c:1795 lookup_one_qstr_excl+0x11f/0x260 fs/namei.c:1633 filename_create+0x297/0x540 fs/namei.c:3980 do_symlinkat+0xf9/0x3a0 fs/namei.c:4587 __do_sys_symlinkat fs/namei.c:4610 [inline] __se_sys_symlinkat fs/namei.c:4607 [inline] __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:4607 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3e73ced469 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff4d40c258 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0032656c69662f2e RCX: 00007f3e73ced469 RDX: 0000000020000200 RSI: 00000000ffffff9c RDI: 00000000200001c0 RBP: 0000000000000000 R08: 00007fff4d40c290 R09: 00007fff4d40c290 R10: 0023706f6f6c2f76 R11: 0000000000000246 R12: 00007fff4d40c27c R13: 0000000000000003 R14: 431bde82d7b634db R15: 00007fff4d40c2b0 </TASK>
Calling ext4_xattr_ibody_find right after reading the inode with ext4_get_inode_loc will lead to a check of the validity of the xattrs, avoiding this problem.
Reported-by: syzbot+0c2508114d912a54ee79@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c2508114d912a54ee79 Fixes: e8e948e7802a ("ext4: let ext4_find_entry handle inline data") Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@igalia.com Link: https://patch.msgid.link/20240821152324.3621860-5-cascardo@igalia.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Baokun Li libaokun1@huawei.com --- fs/ext4/inline.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c index a4128047e63f..2b0b6a74d4fc 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -1654,25 +1654,36 @@ struct buffer_head *ext4_find_inline_entry(struct inode *dir, struct ext4_dir_entry_2 **res_dir, int *has_inline_data) { + struct ext4_xattr_ibody_find is = { + .s = { .not_found = -ENODATA, }, + }; + struct ext4_xattr_info i = { + .name_index = EXT4_XATTR_INDEX_SYSTEM, + .name = EXT4_XATTR_SYSTEM_DATA, + }; int ret; - struct ext4_iloc iloc; void *inline_start; int inline_size;
- ret = ext4_get_inode_loc(dir, &iloc); + ret = ext4_get_inode_loc(dir, &is.iloc); if (ret) return ERR_PTR(ret);
down_read(&EXT4_I(dir)->xattr_sem); + + ret = ext4_xattr_ibody_find(dir, &i, &is); + if (ret) + goto out; + if (!ext4_has_inline_data(dir)) { *has_inline_data = 0; goto out; }
- inline_start = (void *)ext4_raw_inode(&iloc)->i_block + + inline_start = (void *)ext4_raw_inode(&is.iloc)->i_block + EXT4_INLINE_DOTDOT_SIZE; inline_size = EXT4_MIN_INLINE_DATA_SIZE - EXT4_INLINE_DOTDOT_SIZE; - ret = ext4_search_dir(iloc.bh, inline_start, inline_size, + ret = ext4_search_dir(is.iloc.bh, inline_start, inline_size, dir, fname, 0, res_dir); if (ret == 1) goto out_find; @@ -1682,23 +1693,23 @@ struct buffer_head *ext4_find_inline_entry(struct inode *dir, if (ext4_get_inline_size(dir) == EXT4_MIN_INLINE_DATA_SIZE) goto out;
- inline_start = ext4_get_inline_xattr_pos(dir, &iloc); + inline_start = ext4_get_inline_xattr_pos(dir, &is.iloc); inline_size = ext4_get_inline_size(dir) - EXT4_MIN_INLINE_DATA_SIZE;
- ret = ext4_search_dir(iloc.bh, inline_start, inline_size, + ret = ext4_search_dir(is.iloc.bh, inline_start, inline_size, dir, fname, 0, res_dir); if (ret == 1) goto out_find;
out: - brelse(iloc.bh); + brelse(is.iloc.bh); if (ret < 0) - iloc.bh = ERR_PTR(ret); + is.iloc.bh = ERR_PTR(ret); else - iloc.bh = NULL; + is.iloc.bh = NULL; out_find: up_read(&EXT4_I(dir)->xattr_sem); - return iloc.bh; + return is.iloc.bh; }
int ext4_delete_inline_entry(handle_t *handle,
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