| Message ID | 20250114123410.29123-1-chao@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5c1768b6725049e1fcfc841924d65f2872413000 |
| Headers | show |
| Series | [f2fs-dev,v2] f2fs: fix to do sanity check correctly on i_inline_xattr_size | expand |
Hello: This patch was applied to jaegeuk/f2fs.git (dev) by Jaegeuk Kim <jaegeuk@kernel.org>: On Tue, 14 Jan 2025 20:34:10 +0800 you wrote: > syzbot reported an out-of-range access issue as below: > > UBSAN: array-index-out-of-bounds in fs/f2fs/f2fs.h:3292:19 > index 18446744073709550491 is out of range for type '__le32[923]' (aka 'unsigned int[923]') > CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-10689-g7af08b57bcb9 #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:94 [inline] > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 > ubsan_epilogue lib/ubsan.c:231 [inline] > __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429 > read_inline_xattr+0x273/0x280 > lookup_all_xattrs fs/f2fs/xattr.c:341 [inline] > f2fs_getxattr+0x57b/0x13b0 fs/f2fs/xattr.c:533 > vfs_getxattr_alloc+0x472/0x5c0 fs/xattr.c:393 > ima_read_xattr+0x38/0x60 security/integrity/ima/ima_appraise.c:229 > process_measurement+0x117a/0x1fb0 security/integrity/ima/ima_main.c:353 > ima_file_check+0xd9/0x120 security/integrity/ima/ima_main.c:572 > security_file_post_open+0xb9/0x280 security/security.c:3121 > do_open fs/namei.c:3830 [inline] > path_openat+0x2ccd/0x3590 fs/namei.c:3987 > do_file_open_root+0x3a7/0x720 fs/namei.c:4039 > file_open_root+0x247/0x2a0 fs/open.c:1382 > do_handle_open+0x85b/0x9d0 fs/fhandle.c:414 > 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 > > [...] Here is the summary with links: - [f2fs-dev,v2] f2fs: fix to do sanity check correctly on i_inline_xattr_size https://git.kernel.org/jaegeuk/f2fs/c/5c1768b67250 You are awesome, thank you!
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 282fd320bdb3..7de33da8b3ea 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -302,15 +302,6 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page) F2FS_TOTAL_EXTRA_ATTR_SIZE); return false; } - if (f2fs_sb_has_flexible_inline_xattr(sbi) && - f2fs_has_inline_xattr(inode) && - (!fi->i_inline_xattr_size || - fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE)) { - f2fs_warn(sbi, "%s: inode (ino=%lx) has corrupted i_inline_xattr_size: %d, max: %lu", - __func__, inode->i_ino, fi->i_inline_xattr_size, - MAX_INLINE_XATTR_SIZE); - return false; - } if (f2fs_sb_has_compression(sbi) && fi->i_flags & F2FS_COMPR_FL && F2FS_FITS_IN_INODE(ri, fi->i_extra_isize, @@ -320,6 +311,16 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page) } } + if (f2fs_sb_has_flexible_inline_xattr(sbi) && + f2fs_has_inline_xattr(inode) && + (fi->i_inline_xattr_size < MIN_INLINE_XATTR_SIZE || + fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE)) { + f2fs_warn(sbi, "%s: inode (ino=%lx) has corrupted i_inline_xattr_size: %d, min: %lu, max: %lu", + __func__, inode->i_ino, fi->i_inline_xattr_size, + MIN_INLINE_XATTR_SIZE, MAX_INLINE_XATTR_SIZE); + return false; + } + if (!f2fs_sb_has_extra_attr(sbi)) { if (f2fs_sb_has_project_quota(sbi)) { f2fs_warn(sbi, "%s: corrupted inode ino=%lx, wrong feature flag: %u, run fsck to fix.",
syzbot reported an out-of-range access issue as below: UBSAN: array-index-out-of-bounds in fs/f2fs/f2fs.h:3292:19 index 18446744073709550491 is out of range for type '__le32[923]' (aka 'unsigned int[923]') CPU: 0 UID: 0 PID: 5338 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-10689-g7af08b57bcb9 #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:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429 read_inline_xattr+0x273/0x280 lookup_all_xattrs fs/f2fs/xattr.c:341 [inline] f2fs_getxattr+0x57b/0x13b0 fs/f2fs/xattr.c:533 vfs_getxattr_alloc+0x472/0x5c0 fs/xattr.c:393 ima_read_xattr+0x38/0x60 security/integrity/ima/ima_appraise.c:229 process_measurement+0x117a/0x1fb0 security/integrity/ima/ima_main.c:353 ima_file_check+0xd9/0x120 security/integrity/ima/ima_main.c:572 security_file_post_open+0xb9/0x280 security/security.c:3121 do_open fs/namei.c:3830 [inline] path_openat+0x2ccd/0x3590 fs/namei.c:3987 do_file_open_root+0x3a7/0x720 fs/namei.c:4039 file_open_root+0x247/0x2a0 fs/open.c:1382 do_handle_open+0x85b/0x9d0 fs/fhandle.c:414 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 index: 18446744073709550491 (decimal, unsigned long long) = 0xfffffffffffffb9b (hexadecimal) = -1125 (decimal, long long) UBSAN detects that inline_xattr_addr() tries to access .i_addr[-1125]. w/ below testcase, it can reproduce this bug easily: - mkfs.f2fs -f -O extra_attr,flexible_inline_xattr /dev/sdb - mount -o inline_xattr_size=512 /dev/sdb /mnt/f2fs - touch /mnt/f2fs/file - umount /mnt/f2fs - inject.f2fs --node --mb i_inline --nid 4 --val 0x1 /dev/sdb - inject.f2fs --node --mb i_inline_xattr_size --nid 4 --val 2048 /dev/sdb - mount /dev/sdb /mnt/f2fs - getfattr /mnt/f2fs/file The root cause is if metadata of filesystem and inode were fuzzed as below: - extra_attr feature is enabled - flexible_inline_xattr feature is enabled - ri.i_inline_xattr_size = 2048 - F2FS_EXTRA_ATTR bit in ri.i_inline was not set sanity_check_inode() will skip doing sanity check on fi->i_inline_xattr_size, result in using invalid inline_xattr_size later incorrectly, fix it. Meanwhile, let's fix to check lower boundary for .i_inline_xattr_size w/ MIN_INLINE_XATTR_SIZE like we did in parse_options(). There is a related issue reported by syzbot, Qasim Ijaz has anlyzed and fixed it w/ very similar way [1], as discussed, we all agree that it will be better to do sanity check in sanity_check_inode() for fix, so finally, let's fix these two related bugs w/ current patch. Including commit message from Qasim's patch as below, thanks a lot for his contribution. "In f2fs_getxattr(), the function lookup_all_xattrs() allocates a 12-byte (base_size) buffer for an inline extended attribute. However, when __find_inline_xattr() calls __find_xattr(), it uses the macro "list_for_each_xattr(entry, addr)", which starts by calling XATTR_FIRST_ENTRY(addr). This skips a 24-byte struct f2fs_xattr_header at the beginning of the buffer, causing an immediate out-of-bounds read in a 12-byte allocation. The subsequent !IS_XATTR_LAST_ENTRY(entry) check then dereferences memory outside the allocated region, triggering the slab-out-of bounds read. This patch prevents the out-of-bounds read by adding a check to bail out early if inline_size is too small and does not account for the header plus the 4-byte value that IS_XATTR_LAST_ENTRY reads." [1]: https://lore.kernel.org/linux-f2fs-devel/Z32y1rfBY9Qb5ZjM@qasdev.system/ Fixes: 6afc662e68b5 ("f2fs: support flexible inline xattr size") Reported-by: syzbot+69f5379a1717a0b982a1@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/674f4e7d.050a0220.17bd51.004f.GAE@google.com Reported-by: syzbot <syzbot+f5e74075e096e757bdbf@syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=f5e74075e096e757bdbf Tested-by: syzbot <syzbot+f5e74075e096e757bdbf@syzkaller.appspotmail.com> Tested-by: Qasim Ijaz <qasdev00@gmail.com> Signed-off-by: Chao Yu <chao@kernel.org> --- v2: - including commit message from Qasim's patch. fs/f2fs/inode.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)