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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2015-11-20 15:57:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-20 16:17:32 -0800
commit928a477102c4fc6739883415b66987207e3502f4 (patch)
tree1b38ac8017f2427750f11806437271634177b6f8 /fs
parentmm/hugetlbfs: fix bugs in fallocate hole punch of areas with holes (diff)
downloadlinux-dev-928a477102c4fc6739883415b66987207e3502f4.tar.xz
linux-dev-928a477102c4fc6739883415b66987207e3502f4.zip
fat: fix fake_offset handling on error path
For the root directory, . and .. are faked (using dir_emit_dots()) and ctx->pos is reset from 2 to 0. A corrupted root directory could cause fat_get_entry() to fail, but ->iterate() (fat_readdir()) reports progress to the VFS (with ctx->pos rewound to 0), so any following calls to ->iterate() continue to return the same entries again and again. The result is that userspace will never see the end of the directory, causing e.g. 'ls' to hang in a getdents() loop. [hirofumi@mail.parknet.co.jp: cleanup and make sure to correct fake_offset] Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Tested-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Richard Weinberger <richard.weinberger@gmail.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/fat/dir.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 4afc4d9d2e41..8b2127ffb226 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -610,9 +610,9 @@ parse_record:
int status = fat_parse_long(inode, &cpos, &bh, &de,
&unicode, &nr_slots);
if (status < 0) {
- ctx->pos = cpos;
+ bh = NULL;
ret = status;
- goto out;
+ goto end_of_dir;
} else if (status == PARSE_INVALID)
goto record_end;
else if (status == PARSE_NOT_LONGNAME)
@@ -654,8 +654,9 @@ parse_record:
fill_len = short_len;
start_filldir:
- if (!fake_offset)
- ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
+ ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
+ if (fake_offset && ctx->pos < 2)
+ ctx->pos = 2;
if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
if (!dir_emit_dot(file, ctx))
@@ -681,14 +682,19 @@ record_end:
fake_offset = 0;
ctx->pos = cpos;
goto get_new;
+
end_of_dir:
- ctx->pos = cpos;
+ if (fake_offset && cpos < 2)
+ ctx->pos = 2;
+ else
+ ctx->pos = cpos;
fill_failed:
brelse(bh);
if (unicode)
__putname(unicode);
out:
mutex_unlock(&sbi->s_lock);
+
return ret;
}