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 @@ ...@@ -29,7 +29,6 @@
#include <linux/ramoops.h> #include <linux/ramoops.h>
#define RAMOOPS_KERNMSG_HDR "====" #define RAMOOPS_KERNMSG_HDR "===="
#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval))
#define RECORD_SIZE 4096 #define RECORD_SIZE 4096
...@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, ...@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
struct ramoops_context, dump); struct ramoops_context, dump);
unsigned long s1_start, s2_start; unsigned long s1_start, s2_start;
unsigned long l1_cpy, l2_cpy; unsigned long l1_cpy, l2_cpy;
int res; int res, hdr_size;
char *buf; char *buf, *buf_orig;
struct timeval timestamp; struct timeval timestamp;
/* Only dump oopses if dump_oops is set */ /* Only dump oopses if dump_oops is set */
...@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, ...@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
return; return;
buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE)); buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
buf_orig = buf;
memset(buf, '\0', RECORD_SIZE); memset(buf, '\0', RECORD_SIZE);
res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR); res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
buf += res; buf += res;
...@@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper, ...@@ -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); res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
buf += res; buf += res;
l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE)); hdr_size = buf - buf_orig;
l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy); 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; s2_start = l2 - l2_cpy;
s1_start = l1 - l1_cpy; s1_start = l1 - l1_cpy;
......
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