affs: fix remount failure when there are no options changed

Commit c8f33d0bec ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: c8f33d0bec ("affs: kstrdup() memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v4.1+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mikulas Patocka 2016-05-24 22:48:33 +02:00 committed by Linus Torvalds
parent 44d51706b4
commit 01d6e08711
1 changed files with 3 additions and 2 deletions

View File

@ -528,7 +528,7 @@ affs_remount(struct super_block *sb, int *flags, char *data)
char *prefix = NULL;
new_opts = kstrdup(data, GFP_KERNEL);
if (!new_opts)
if (data && !new_opts)
return -ENOMEM;
pr_debug("%s(flags=0x%x,opts=\"%s\")\n", __func__, *flags, data);
@ -546,6 +546,7 @@ affs_remount(struct super_block *sb, int *flags, char *data)
}
flush_delayed_work(&sbi->sb_work);
if (new_opts)
replace_mount_options(sb, new_opts);
sbi->s_flags = mount_flags;