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authorPaul Menage <menage@google.com>2008-06-12 15:21:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-06-12 18:05:41 -0700
commit6c826818ff55eae7702b778b5f8bdf765af3b2af (patch)
treedab51aca0d7b86ccdc820894a96fad163f3fcb91
parentbcf8039ed45f56013c4afea5520bca7d909e5e61 (diff)
downloadlinux-6c826818ff55eae7702b778b5f8bdf765af3b2af.tar.gz
/proc/sysvipc/shm: fix 32-bit truncation of segment sizes
sysvipc_shm_proc_show() picks between format strings (based on the expected maximum length of a SHM segment) in a way that prevents gcc from performing format checks on the seq_printf() parameters. This hid two format errors - shp->shm_segsz and shp->shm_nattach are both unsigned long, but were being printed as unsigned int and signed int respectively. This leads to 32-bit truncation of SHM segment sizes reported in /proc/sysvipc/shm. (And for nattach, but that's less of a problem for most users). This patch makes the format string directly visible to gcc's format specifier checker, and fixes the two broken format specifiers. Signed-off-by: Paul Menage <menage@google.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--ipc/shm.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index d05f6b56499..790240cd067 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1058,16 +1058,16 @@ asmlinkage long sys_shmdt(char __user *shmaddr)
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
{
struct shmid_kernel *shp = it;
- char *format;
-#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
-#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
+#if BITS_PER_LONG <= 32
+#define SIZE_SPEC "%10lu"
+#else
+#define SIZE_SPEC "%21lu"
+#endif
- if (sizeof(size_t) <= sizeof(int))
- format = SMALL_STRING;
- else
- format = BIG_STRING;
- return seq_printf(s, format,
+ return seq_printf(s,
+ "%10d %10d %4o " SIZE_SPEC " %5u %5u "
+ "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
shp->shm_perm.key,
shp->shm_perm.id,
shp->shm_perm.mode,