Subject: [merged] ipcshm-correct-error-return-value-in-shmctl-shm_unlock.patch 
removed from -mm tree
To: 
[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected]
From: [email protected]
Date: Fri, 22 Nov 2013 13:22:01 -0800


The patch titled
     Subject: ipc,shm: correct error return value in shmctl (SHM_UNLOCK)
has been removed from the -mm tree.  Its filename was
     ipcshm-correct-error-return-value-in-shmctl-shm_unlock.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Jesper Nilsson <[email protected]>
Subject: ipc,shm: correct error return value in shmctl (SHM_UNLOCK)

2caacaa82a51b78 ("ipc,shm: shorten critical region for shmctl")
restructured the ipc shm to shorten critical region, but introduced a path
where the return value could be -EPERM, even if the operation actually was
performed.

Before the commit, the err return value was reset by the return value from
security_shm_shmctl() after the if (!ns_capable(...)) statement.

Now, we still exit the if statement with err set to -EPERM, and in the
case of SHM_UNLOCK, it is not reset at all, and used as the return value
from shmctl.

To fix this, we only set err when errors occur, leaving the fallthrough
case alone.

Signed-off-by: Jesper Nilsson <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Al Viro <[email protected]>
Cc: <[email protected]>    [3.12.x]
Signed-off-by: Andrew Morton <[email protected]>
---

 ipc/shm.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff -puN ipc/shm.c~ipcshm-correct-error-return-value-in-shmctl-shm_unlock 
ipc/shm.c
--- a/ipc/shm.c~ipcshm-correct-error-return-value-in-shmctl-shm_unlock
+++ a/ipc/shm.c
@@ -977,12 +977,15 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int,
                ipc_lock_object(&shp->shm_perm);
                if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
                        kuid_t euid = current_euid();
-                       err = -EPERM;
                        if (!uid_eq(euid, shp->shm_perm.uid) &&
-                           !uid_eq(euid, shp->shm_perm.cuid))
+                           !uid_eq(euid, shp->shm_perm.cuid)) {
+                               err = -EPERM;
                                goto out_unlock0;
-                       if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
+                       }
+                       if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
+                               err = -EPERM;
                                goto out_unlock0;
+                       }
                }
 
                shm_file = shp->shm_file;
_

Patches currently in -mm which might be from [email protected] are

origin.patch

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