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authorKevin Wolf <kwolf@redhat.com>2015-10-13 09:38:50 +0200
committerMichael Tokarev <mjt@tls.msk.ru>2015-11-06 15:42:37 +0300
commit5accecb3a6b49d8ca79684179610583e9c7c1bf5 (patch)
treec25fc582b801c29a2b9ccebb14921cf388eb6433 /gdbstub.c
parent3c15d3a45045de82c744c49ff471d4c7ba405187 (diff)
downloadqemu-arm-5accecb3a6b49d8ca79684179610583e9c7c1bf5.tar.gz
gdbstub: Fix buffer overflows in gdb_handle_packet()
Some places in gdb_handle_packet() can get an arbitrary length (most times directly from the client) and either didn't check it at all or checked against the wrong value, potentially causing buffer overflows. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'gdbstub.c')
-rw-r--r--gdbstub.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/gdbstub.c b/gdbstub.c
index d2c95b5d1e..9c29aa0e87 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -956,6 +956,13 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
if (*p == ',')
p++;
len = strtoull(p, NULL, 16);
+
+ /* memtohex() doubles the required space */
+ if (len > MAX_PACKET_LENGTH / 2) {
+ put_packet (s, "E22");
+ break;
+ }
+
if (target_memory_rw_debug(s->g_cpu, addr, mem_buf, len, false) != 0) {
put_packet (s, "E14");
} else {
@@ -970,6 +977,12 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
len = strtoull(p, (char **)&p, 16);
if (*p == ':')
p++;
+
+ /* hextomem() reads 2*len bytes */
+ if (len > strlen(p) / 2) {
+ put_packet (s, "E22");
+ break;
+ }
hextomem(mem_buf, p, len);
if (target_memory_rw_debug(s->g_cpu, addr, mem_buf, len,
true) != 0) {
@@ -1107,7 +1120,8 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
cpu = find_cpu(thread);
if (cpu != NULL) {
cpu_synchronize_state(cpu);
- len = snprintf((char *)mem_buf, sizeof(mem_buf),
+ /* memtohex() doubles the required space */
+ len = snprintf((char *)mem_buf, sizeof(buf) / 2,
"CPU#%d [%s]", cpu->cpu_index,
cpu->halted ? "halted " : "running");
memtohex(buf, mem_buf, len);
@@ -1136,8 +1150,8 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
put_packet(s, "E01");
break;
}
- hextomem(mem_buf, p + 5, len);
len = len / 2;
+ hextomem(mem_buf, p + 5, len);
mem_buf[len++] = 0;
qemu_chr_be_write(s->mon_chr, mem_buf, len);
put_packet(s, "OK");