The patch titled
Subject: ipc: clamp msgmni and shmmni to the real IPC_MNI limit
has been added to the -mm tree. Its filename is
ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit.patch
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From: Waiman Long <longman@xxxxxxxxxx>
Subject: ipc: clamp msgmni and shmmni to the real IPC_MNI limit
A user can write arbitrary integer values to msgmni and shmmni sysctl
parameters without getting error, but the actual limit is really IPC_MNI
(32k). This can mislead users as they think they can get a value that is
not real.
Enforcing the limit by failing the sysctl parameter write, however, can
break existing user applications. Instead, the clamping version of the
sysctl parameter range checking API is used to enforce the limit without
failing existing user code. Users can easily figure out if the sysctl
parameter value is out of range by either reading back the parameter value
or checking the kernel ring buffer for warning.
Link: http://lkml.kernel.org/r/1519059231-2456-4-git-send-email-longman@xxxxxxxxxx
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Cc: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/ipc_sysctl.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff -puN ipc/ipc_sysctl.c~ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit ipc/ipc_sysctl.c
--- a/ipc/ipc_sysctl.c~ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit
+++ a/ipc/ipc_sysctl.c
@@ -46,7 +46,8 @@ static int proc_ipc_dointvec_minmax(stru
memcpy(&ipc_table, table, sizeof(ipc_table));
ipc_table.data = get_ipc(table);
- return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
+ return proc_dointvec_clamp_minmax(&ipc_table, write, buffer, lenp,
+ ppos);
}
static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
@@ -99,6 +100,7 @@ static int proc_ipc_auto_msgmni(struct c
static int zero;
static int one = 1;
static int int_max = INT_MAX;
+static int ipc_mni = IPCMNI;
static struct ctl_table ipc_kern_table[] = {
{
@@ -120,7 +122,9 @@ static struct ctl_table ipc_kern_table[]
.data = &init_ipc_ns.shm_ctlmni,
.maxlen = sizeof(init_ipc_ns.shm_ctlmni),
.mode = 0644,
- .proc_handler = proc_ipc_dointvec,
+ .proc_handler = proc_ipc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &ipc_mni,
},
{
.procname = "shm_rmid_forced",
@@ -147,7 +151,7 @@ static struct ctl_table ipc_kern_table[]
.mode = 0644,
.proc_handler = proc_ipc_dointvec_minmax,
.extra1 = &zero,
- .extra2 = &int_max,
+ .extra2 = &ipc_mni,
},
{
.procname = "auto_msgmni",
_
Patches currently in -mm which might be from longman@xxxxxxxxxx are
list_lru-prefetch-neighboring-list-entries-before-acquiring-lock.patch
sysctl-add-range-clamping-intvec-helper-functions.patch
sysctl-warn-when-a-clamped-sysctl-parameter-is-set-out-of-range.patch
ipc-clamp-msgmni-and-shmmni-to-the-real-ipc_mni-limit.patch
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