The patch titled
Subject: kernel/sysctl.c: detect overflows when converting to int
has been added to the -mm tree. Its filename is
sysctl-detect-overflows-when-converting-to-int.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/sysctl-detect-overflows-when-converting-to-int.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/sysctl-detect-overflows-when-converting-to-int.patch
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------------------------------------------------------
From: Heinrich Schuchardt <xypron.glpk@xxxxxx>
Subject: kernel/sysctl.c: detect overflows when converting to int
When converting unsigned long to int overflows may occur. These currently
are not detected when writing to the sysctl file system.
E.g. on a system where int has 32 bits and long has 64 bits
echo 0x800001234 > /proc/sys/kernel/threads-max
has the same effect as
echo 0x1234 > /proc/sys/kernel/threads-max
The patch adds the missing check in do_proc_dointvec_conv.
With the patch an overflow will result in an error EINVAL when writing to
the the sysctl file system.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sysctl.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff -puN kernel/sysctl.c~sysctl-detect-overflows-when-converting-to-int kernel/sysctl.c
--- a/kernel/sysctl.c~sysctl-detect-overflows-when-converting-to-int
+++ a/kernel/sysctl.c
@@ -1980,7 +1980,15 @@ static int do_proc_dointvec_conv(bool *n
int write, void *data)
{
if (write) {
- *valp = *negp ? -*lvalp : *lvalp;
+ if (*negp) {
+ if (*lvalp > (unsigned long) INT_MAX + 1)
+ return -EINVAL;
+ *valp = -*lvalp;
+ } else {
+ if (*lvalp > (unsigned long) INT_MAX)
+ return -EINVAL;
+ *valp = *lvalp;
+ }
} else {
int val = *valp;
if (val < 0) {
_
Patches currently in -mm which might be from xypron.glpk@xxxxxx are
kernel-forkc-new-function-for-max_threads.patch
kernel-forkc-avoid-division-by-zero.patch
kernel-forkc-avoid-division-by-zero-fix.patch
kernel-forkc-avoid-division-by-zero-fix-fix.patch
kernel-sysctlc-threads-max-observe-limits.patch
doc-sysctl-kerneltxt-document-threads-max.patch
doc-sysctl-kerneltxt-document-threads-max-fix.patch
sysctl-detect-overflows-when-converting-to-int.patch
linux-next.patch
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