Attachment 28230 Details for Bug 65424

[patch] This fixes the real problem

xattr-sharing-bug.diff (text/plain), 1.96 KB, created by Andreas Gruenbacher on 2005-02-06 02:06:51 UTC

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Creator: Andreas Gruenbacher

Created: 2005-02-06 02:06:51 UTC

Size: 1.96 KB

patch

obsolete

>From: Andreas Gruenbacher <agruen@suse.de>
>Subject: Fix long-standing xattr sharing bug
>References: 50424
>
>When looking for identical xattr blocks to share we were not comparing
>the name_index fields.  This could lead to false sharing when two xattr
>blocks ended up with identical attribute names and values, and the only
>difference was in name_index.  Specifically this could trigger with
>default acls.  Because acls are cached, the bug was hidden until the
>next reload of the affected inode.
>
>  $ mkdir -m 700 a b
>  $ setfacl -m u:bin:rwx a
>	< acl of a goes in the mbcache
>
>  $ setfacl -dm u:bin:rwx b
>	< acl of b differs only in name_index, so a's acl is reused
>
>  $ getfacl b
>	< shows the result from the inode cache
>
>  < empty inode cache (remount, etc.)
>
>  $ getfacl b
>	< shows an access acl instead of a default acl.
>
>Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
>
>Index: linux-2.6.11-rc3/fs/ext2/xattr.c
>===================================================================
>--- linux-2.6.11-rc3.orig/fs/ext2/xattr.c
>+++ linux-2.6.11-rc3/fs/ext2/xattr.c
>@@ -881,6 +881,7 @@ ext2_xattr_cmp(struct ext2_xattr_header 
> 		if (IS_LAST_ENTRY(entry2))
> 			return 1;
> 		if (entry1->e_hash != entry2->e_hash ||
>+		    entry1->e_name_index != entry2->e_name_index ||
> 		    entry1->e_name_len != entry2->e_name_len ||
> 		    entry1->e_value_size != entry2->e_value_size ||
> 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
>Index: linux-2.6.11-rc3/fs/ext3/xattr.c
>===================================================================
>--- linux-2.6.11-rc3.orig/fs/ext3/xattr.c
>+++ linux-2.6.11-rc3/fs/ext3/xattr.c
>@@ -1162,6 +1162,7 @@ ext3_xattr_cmp(struct ext3_xattr_header 
> 		if (IS_LAST_ENTRY(entry2))
> 			return 1;
> 		if (entry1->e_hash != entry2->e_hash ||
>+		    entry1->e_name_index != entry2->e_name_index ||
> 		    entry1->e_name_len != entry2->e_name_len ||
> 		    entry1->e_value_size != entry2->e_value_size ||
> 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))

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