Commit-ID: cdf8073d6b2c6c5a3cd6ce0e6c1297157f7f99ba
Gitweb: http://git.kernel.org/tip/cdf8073d6b2c6c5a3cd6ce0e6c1297157f7f99ba
Author: Ian Schram <ischram@xxxxxxxxxx>
AuthorDate: Fri, 18 Sep 2009 21:26:26 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 19 Sep 2009 19:32:55 +0200
perf_counter: Fix perf_copy_attr() pointer arithmetic
There is still some weird code in per_copy_attr(). Which supposedly
checks that all bytes trailing a struct are zero.
It doesn't seem to get pointer arithmetic right. Since it
increments an iterating pointer by sizeof(unsigned long) rather
than 1.
Signed-off-by: Ian Schram <ischram@xxxxxxxxxx>
[ v2: clean up the messy PTR_ALIGN logic as well. ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx> # for v2.6.31.x
LKML-Reference: <4AB3DEE2.3030600@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/perf_counter.c | 20 ++++++++++----------
1 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index d5899b6..cc768ab 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -4208,8 +4208,8 @@ done:
static int perf_copy_attr(struct perf_counter_attr __user *uattr,
struct perf_counter_attr *attr)
{
- int ret;
u32 size;
+ int ret;
if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
return -EFAULT;
@@ -4234,19 +4234,19 @@ static int perf_copy_attr(struct perf_counter_attr __user *uattr,
/*
* If we're handed a bigger struct than we know of,
- * ensure all the unknown bits are 0.
+ * ensure all the unknown bits are 0 - i.e. new
+ * user-space does not rely on any kernel feature
+ * extensions we dont know about yet.
*/
if (size > sizeof(*attr)) {
- unsigned long val;
- unsigned long __user *addr;
- unsigned long __user *end;
+ unsigned char __user *addr;
+ unsigned char __user *end;
+ unsigned char val;
- addr = PTR_ALIGN((void __user *)uattr + sizeof(*attr),
- sizeof(unsigned long));
- end = PTR_ALIGN((void __user *)uattr + size,
- sizeof(unsigned long));
+ addr = (void __user *)uattr + sizeof(*attr);
+ end = (void __user *)uattr + size;
- for (; addr < end; addr += sizeof(unsigned long)) {
+ for (; addr < end; addr++) {
ret = get_user(val, addr);
if (ret)
return ret;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|