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(). > Thanks! > -Lukas > >> >> 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; > > Again no data, no reason for backing off. orig_data could be NULL if *data is NULL, or if kstrdup got ENOMEM. Anyway, please describe how the bug can arise, and then we can better evaluate the change. Thanks! -Eric >> 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; > > > This does not seem right, it there is no data we will end with ENOMEM > for no reason. > >> /* 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 >> > -- 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
