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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2008-01-12 14:06:34 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2008-01-14 12:17:39 -0800
commit3093d39c9361dae001efaea9279b0b23e38f049c (patch)
parenteae2a53f7fea8c99fa56c2b1d8b554507fab4ad7 (diff)
Use access mode instead of open flags to determine needed permissions (CVE-2008-0001)
patch 974a9f0b47da74e28f68b9c8645c3786aa5ace1a in mainline Way back when (in commit 834f2a4a1554dc5b2598038b3fe8703defcbe467, aka "VFS: Allow the filesystem to return a full file pointer on open intent" to be exact), Trond changed the open logic to keep track of the original flags to a file open, in order to pass down the the intent of a dentry lookup to the low-level filesystem. However, when doing that reorganization, it changed the meaning of namei_flags, and thus inadvertently changed the test of access mode for directories (and RO filesystem) to use the wrong flag. So fix those test back to use access mode ("acc_mode") rather than the open flag ("flag"). Issue noticed by Bill Roman at Datalight. Reported-and-tested-by: Bill Roman <bill.roman@datalight.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index a83160acd748..314afe608891 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1576,7 +1576,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
if (S_ISLNK(inode->i_mode))
return -ELOOP;
- if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE))
+ if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE))
return -EISDIR;
error = vfs_permission(nd, acc_mode);
@@ -1595,7 +1595,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
return -EACCES;
flag &= ~O_TRUNC;
- } else if (IS_RDONLY(inode) && (flag & FMODE_WRITE))
+ } else if (IS_RDONLY(inode) && (acc_mode & MAY_WRITE))
return -EROFS;
* An append-only file must be opened in append mode for writing.