[PATCH -V5 02/24] vfs: Pass all mask flags down to iop->check_acl

From: Aneesh Kumar K.V
Date: Wed Feb 23 2011 - 09:01:45 EST


From: Andreas Gruenbacher <agruen@xxxxxxx>

Some file permission models differentiate between writing to a file
(MAY_WRITE) and appending to it (MAY_WRITE | MAY_APPEND). Pass all the
mask flags down to iop->check_acl so that filesystems can distinguish
between writing and appending.

All users of iop->check_acl pass the mask value back into
posix_acl_permission(); strip off the additional mask flags there.

Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 4 +---
fs/posix_acl.c | 2 ++
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index b01eab8..f09ab1f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -174,8 +174,6 @@ static int acl_permission_check(struct inode *inode, int mask, unsigned int flag
{
umode_t mode = inode->i_mode;

- mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
-
if (current_fsuid() == inode->i_uid)
mode >>= 6;
else {
@@ -192,7 +190,7 @@ static int acl_permission_check(struct inode *inode, int mask, unsigned int flag
/*
* If the DACs are ok we don't need any capability check.
*/
- if ((mask & ~mode) == 0)
+ if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC) & ~mode) == 0)
return 0;
return -EACCES;
}
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index b1cf6bf..ad40df2 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -222,6 +222,8 @@ posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want)
const struct posix_acl_entry *pa, *pe, *mask_obj;
int found = 0;

+ want &= MAY_READ | MAY_WRITE | MAY_EXEC;
+
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
--
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/