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author | Dan Carpenter <dan.carpenter@oracle.com> | 2014-04-08 12:23:09 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-14 06:50:04 -0700 |
commit | f9f80fa9755d955425d99220e018ac9618f642f5 (patch) | |
tree | 9701c71d8662531944ce5e949983f566db3fa0ac | |
parent | 64eb5b6911e1edbb5db537fe1fa27ac936c1dd0c (diff) | |
download | lwn-f9f80fa9755d955425d99220e018ac9618f642f5.tar.gz lwn-f9f80fa9755d955425d99220e018ac9618f642f5.zip |
isdnloop: several buffer overflows
[ Upstream commit 7563487cbf865284dcd35e9ef5a95380da046737 ]
There are three buffer overflows addressed in this patch.
1) In isdnloop_fake_err() we add an 'E' to a 60 character string and
then copy it into a 60 character buffer. I have made the destination
buffer 64 characters and I'm changed the sprintf() to a snprintf().
2) In isdnloop_parse_cmd(), p points to a 6 characters into a 60
character buffer so we have 54 characters. The ->eazlist[] is 11
characters long. I have modified the code to return if the source
buffer is too long.
3) In isdnloop_command() the cbuf[] array was 60 characters long but the
max length of the string then can be up to 79 characters. I made the
cbuf array 80 characters long and changed the sprintf() to snprintf().
I also removed the temporary "dial" buffer and changed it to use "p"
directly.
Unfortunately, we pass the "cbuf" string from isdnloop_command() to
isdnloop_writecmd() which truncates anything over 60 characters to make
it fit in card->omsg[]. (It can accept values up to 255 characters so
long as there is a '\n' character every 60 characters). For now I have
just fixed the memory corruption bug and left the other problems in this
driver alone.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/isdn/isdnloop/isdnloop.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/isdn/isdnloop/isdnloop.c b/drivers/isdn/isdnloop/isdnloop.c index e1f8748ff25d..5a4da94aefb0 100644 --- a/drivers/isdn/isdnloop/isdnloop.c +++ b/drivers/isdn/isdnloop/isdnloop.c @@ -518,9 +518,9 @@ static isdnloop_stat isdnloop_cmd_table[] = static void isdnloop_fake_err(isdnloop_card *card) { - char buf[60]; + char buf[64]; - sprintf(buf, "E%s", card->omsg); + snprintf(buf, sizeof(buf), "E%s", card->omsg); isdnloop_fake(card, buf, -1); isdnloop_fake(card, "NAK", -1); } @@ -903,6 +903,8 @@ isdnloop_parse_cmd(isdnloop_card *card) case 7: /* 0x;EAZ */ p += 3; + if (strlen(p) >= sizeof(card->eazlist[0])) + break; strcpy(card->eazlist[ch - 1], p); break; case 8: @@ -1133,7 +1135,7 @@ isdnloop_command(isdn_ctrl *c, isdnloop_card *card) { ulong a; int i; - char cbuf[60]; + char cbuf[80]; isdn_ctrl cmd; isdnloop_cdef cdef; @@ -1198,7 +1200,6 @@ isdnloop_command(isdn_ctrl *c, isdnloop_card *card) break; if ((c->arg & 255) < ISDNLOOP_BCH) { char *p; - char dial[50]; char dcode[4]; a = c->arg; @@ -1210,10 +1211,10 @@ isdnloop_command(isdn_ctrl *c, isdnloop_card *card) } else /* Normal Dial */ strcpy(dcode, "CAL"); - strcpy(dial, p); - sprintf(cbuf, "%02d;D%s_R%s,%02d,%02d,%s\n", (int) (a + 1), - dcode, dial, c->parm.setup.si1, - c->parm.setup.si2, c->parm.setup.eazmsn); + snprintf(cbuf, sizeof(cbuf), + "%02d;D%s_R%s,%02d,%02d,%s\n", (int) (a + 1), + dcode, p, c->parm.setup.si1, + c->parm.setup.si2, c->parm.setup.eazmsn); i = isdnloop_writecmd(cbuf, strlen(cbuf), 0, card); } break; |