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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 12:08:26 -0800
commit53d06121542c36ec0f0e5504c8358a768e25cb9a (patch)
parentfe18bd1cf0827a654fd75079101c551b17e1c639 (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 5e2d98d10c5d..8e209cecc3b8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1543,7 +1543,7 @@ 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);
@@ -1562,7 +1562,7 @@ 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.