On Thu, 2011-06-09 at 22:51 +0800, Eric Sandeen wrote: > On 6/9/11 4:24 AM, Lukas Czerner wrote: > > On Thu, 9 Jun 2011, Shaohua Li wrote: > > > >> orig_data could be NULL. > > > > Now, that is the commit description :). Could you please be more > > descriptive in the "descritpion" ? Also the subject is not right either, > > please see Documentation/SubmittingPatches > > Yes; if possible please use the commit message to describe how/why orig_data > can be NULL; a testcase if one exists; the resulting flaw (null pointer deref?) > etc. > > something like: > > Subject: [PATCH] ext4: check for NULL orig_data pointer in mount paths > > The orig_data pointer in ext4_fill_super() and ext4_remount() > can be null if < ??? >, which can lead to < ??? > in the mount > and remount paths. This can be demonstrated by < ??? >. > To avoid this, we can simply test for the null pointer > and return an error in ext4_fill_super() and ext4_remount(). I thought the reason is pretty straightforward, anyway here is the updated patch. Subject: [patch]ext4: check NULL pointer for mount and remount orig_data could be NULL, because the memory allocation of kstrdup() could fail. Add the NULL check. Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx> diff --git a/fs/ext4/super.c b/fs/ext4/super.c index cc5c157..45fc255 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3057,6 +3057,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO; ext4_group_t first_not_zeroed; + if (!orig_data) + return ret; sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); if (!sbi) goto out_free_orig; @@ -4285,6 +4287,8 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) #endif char *orig_data = kstrdup(data, GFP_KERNEL); + if (!orig_data) + return -ENOMEM; /* Store the original options */ lock_super(sb); old_sb_flags = sb->s_flags; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
