* [PATCH] powerpc: Prevent unsigned wrap in htab_dt_scan_page_sizes()
@ 2009-10-14 12:12 Roel Kluin
2009-10-14 21:29 ` Paul Mackerras
0 siblings, 1 reply; 2+ messages in thread
From: Roel Kluin @ 2009-10-14 12:12 UTC (permalink / raw)
To: paulus, benh, linuxppc-dev; +Cc: Andrew Morton
Check to prevent unsigned wrap of size before subtraction.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
Is this maybe better or are we certain that size can't wrap?
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 1ade7eb..dd2d263 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -287,7 +287,7 @@ static int __init htab_dt_scan_page_sizes(unsigned long node,
DBG("Page sizes from device-tree:\n");
size /= 4;
cur_cpu_spec->cpu_features &= ~(CPU_FTR_16M_PAGE);
- while(size > 0) {
+ while(size >= 3) {
unsigned int shift = prop[0];
unsigned int slbenc = prop[1];
unsigned int lpnum = prop[2];
@@ -296,7 +296,7 @@ static int __init htab_dt_scan_page_sizes(unsigned long node,
int idx = -1;
size -= 3; prop += 3;
- while(size > 0 && lpnum) {
+ while(size >= 2 && lpnum) {
if (prop[0] == shift)
lpenc = prop[1];
prop += 2; size -= 2;
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] powerpc: Prevent unsigned wrap in htab_dt_scan_page_sizes()
2009-10-14 12:12 [PATCH] powerpc: Prevent unsigned wrap in htab_dt_scan_page_sizes() Roel Kluin
@ 2009-10-14 21:29 ` Paul Mackerras
0 siblings, 0 replies; 2+ messages in thread
From: Paul Mackerras @ 2009-10-14 21:29 UTC (permalink / raw)
To: Roel Kluin; +Cc: Andrew Morton, linuxppc-dev
Roel Kluin writes:
> Check to prevent unsigned wrap of size before subtraction.
>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> Is this maybe better or are we certain that size can't wrap?
Patch looks good, though while you're at it, you could add a space
after the "while".
Acked-by: Paul Mackerras <paulus@samba.org>
^ permalink raw reply [flat|nested] 2+ messages in thread
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