Commit 1873bb81 authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Linus Torvalds

RAMOOPS: Don't overflow over non-allocated regions

The current code mis-calculates the ramoops header size, leading to an
overflow over the next record at best, or over a non-allocated region at
worst.  Fix that calculation.
Signed-off-by: default avatarAhmed S. Darwish <darwish.07@gmail.com>
Acked-by: default avatarMarco Stornelli <marco.stornelli@gmail.com>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ffc96d62
......@@ -29,7 +29,6 @@
#include <linux/ramoops.h>
#define RAMOOPS_KERNMSG_HDR "===="
#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval))
#define RECORD_SIZE 4096
......@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
struct ramoops_context, dump);
unsigned long s1_start, s2_start;
unsigned long l1_cpy, l2_cpy;
int res;
char *buf;
int res, hdr_size;
char *buf, *buf_orig;
struct timeval timestamp;
/* Only dump oopses if dump_oops is set */
......@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
return;
buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
buf_orig = buf;
memset(buf, '\0', RECORD_SIZE);
res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
buf += res;
......@@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
buf += res;
l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));
l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);
hdr_size = buf - buf_orig;
l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);
s2_start = l2 - l2_cpy;
s1_start = l1 - l1_cpy;
......
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