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| author | Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> | 2018-08-23 17:00:25 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-15 09:40:38 +0200 |
| commit | fed5bd3352a3fbf9494449ffee3b4bab5e8cc3a6 (patch) | |
| tree | 39a5a7d5872fd019d330cdfaf15efcf908b73bbe /fs/hfsplus | |
| parent | ccbe4990bb1bf84a425015f68d7e7a2b9d1b3f8a (diff) | |
| download | linux-stable-fed5bd3352a3fbf9494449ffee3b4bab5e8cc3a6.tar.gz linux-stable-fed5bd3352a3fbf9494449ffee3b4bab5e8cc3a6.tar.bz2 linux-stable-fed5bd3352a3fbf9494449ffee3b4bab5e8cc3a6.zip | |
hfsplus: fix NULL dereference in hfsplus_lookup()
[ Upstream commit a7ec7a4193a2eb3b5341243fc0b621c1ac9e4ec4 ]
An HFS+ filesystem can be mounted read-only without having a metadata
directory, which is needed to support hardlinks. But if the catalog
data is corrupted, a directory lookup may still find dentries claiming
to be hardlinks.
hfsplus_lookup() does check that ->hidden_dir is not NULL in such a
situation, but mistakenly does so after dereferencing it for the first
time. Reorder this check to prevent a crash.
This happens when looking up corrupted catalog data (dentry) on a
filesystem with no metadata directory (this could only ever happen on a
read-only mount). Wen Xu sent the replication steps in detail to the
fsdevel list: https://bugzilla.kernel.org/show_bug.cgi?id=200297
Link: http://lkml.kernel.org/r/20180712215344.q44dyrhymm4ajkao@eaf
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reported-by: Wen Xu <wen.xu@gatech.edu>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/hfsplus')
| -rw-r--r-- | fs/hfsplus/dir.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c index d0f39dcbb58e..2b6e2ad57bf9 100644 --- a/fs/hfsplus/dir.c +++ b/fs/hfsplus/dir.c @@ -77,13 +77,13 @@ again: cpu_to_be32(HFSP_HARDLINK_TYPE) && entry.file.user_info.fdCreator == cpu_to_be32(HFSP_HFSPLUS_CREATOR) && + HFSPLUS_SB(sb)->hidden_dir && (entry.file.create_date == HFSPLUS_I(HFSPLUS_SB(sb)->hidden_dir)-> create_date || entry.file.create_date == HFSPLUS_I(d_inode(sb->s_root))-> - create_date) && - HFSPLUS_SB(sb)->hidden_dir) { + create_date)) { struct qstr str; char name[32]; |