mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-09 14:50:05 +00:00
socket: Check lengths before advancing pointer in CMSG_NXTHDR
The inline and library functions that the CMSG_NXTHDR macro may expand to increment the pointer to the header before checking the stride of the increment against available space. Since C only allows incrementing pointers to one past the end of an array, the increment must be done after a length check. This commit fixes that and includes a regression test for CMSG_FIRSTHDR and CMSG_NXTHDR. The Linux, Hurd, and generic headers are all changed. Tested on Linux on armv7hl, i686, x86_64, aarch64, ppc64le, and s390x. [BZ #28846] Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
parent
521d540562
commit
9c443ac455
@ -245,6 +245,12 @@ struct cmsghdr
|
||||
+ CMSG_ALIGN (sizeof (struct cmsghdr)))
|
||||
#define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
|
||||
|
||||
/* Given a length, return the additional padding necessary such that
|
||||
len + __CMSG_PADDING(len) == CMSG_ALIGN (len). */
|
||||
#define __CMSG_PADDING(len) ((sizeof (size_t) \
|
||||
- ((len) & (sizeof (size_t) - 1))) \
|
||||
& (sizeof (size_t) - 1))
|
||||
|
||||
extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
struct cmsghdr *__cmsg) __THROW;
|
||||
#ifdef __USE_EXTERN_INLINES
|
||||
@ -254,18 +260,38 @@ extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
_EXTERN_INLINE struct cmsghdr *
|
||||
__NTH (__cmsg_nxthdr (struct msghdr *__mhdr, struct cmsghdr *__cmsg))
|
||||
{
|
||||
/* We may safely assume that __cmsg lies between __mhdr->msg_control and
|
||||
__mhdr->msg_controllen because the user is required to obtain the first
|
||||
cmsg via CMSG_FIRSTHDR, set its length, then obtain subsequent cmsgs
|
||||
via CMSG_NXTHDR, setting lengths along the way. However, we don't yet
|
||||
trust the value of __cmsg->cmsg_len and therefore do not use it in any
|
||||
pointer arithmetic until we check its value. */
|
||||
|
||||
unsigned char * __msg_control_ptr = (unsigned char *) __mhdr->msg_control;
|
||||
unsigned char * __cmsg_ptr = (unsigned char *) __cmsg;
|
||||
|
||||
size_t __size_needed = sizeof (struct cmsghdr)
|
||||
+ __CMSG_PADDING (__cmsg->cmsg_len);
|
||||
|
||||
/* The current header is malformed, too small to be a full header. */
|
||||
if ((size_t) __cmsg->cmsg_len < sizeof (struct cmsghdr))
|
||||
/* The kernel header does this so there may be a reason. */
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* There isn't enough space between __cmsg and the end of the buffer to
|
||||
hold the current cmsg *and* the next one. */
|
||||
if (((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr)
|
||||
< __size_needed)
|
||||
|| ((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr
|
||||
- __size_needed)
|
||||
< __cmsg->cmsg_len))
|
||||
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* Now, we trust cmsg_len and can use it to find the next header. */
|
||||
__cmsg = (struct cmsghdr *) ((unsigned char *) __cmsg
|
||||
+ CMSG_ALIGN (__cmsg->cmsg_len));
|
||||
if ((unsigned char *) (__cmsg + 1) > ((unsigned char *) __mhdr->msg_control
|
||||
+ __mhdr->msg_controllen)
|
||||
|| ((unsigned char *) __cmsg + CMSG_ALIGN (__cmsg->cmsg_len)
|
||||
> ((unsigned char *) __mhdr->msg_control + __mhdr->msg_controllen)))
|
||||
/* No more entries. */
|
||||
return (struct cmsghdr *) 0;
|
||||
return __cmsg;
|
||||
}
|
||||
#endif /* Use `extern inline'. */
|
||||
|
@ -34,6 +34,7 @@ routines := accept bind connect getpeername getsockname getsockopt \
|
||||
tests := \
|
||||
tst-accept4 \
|
||||
tst-sockopt \
|
||||
tst-cmsghdr \
|
||||
# tests
|
||||
|
||||
tests-internal := \
|
||||
|
92
socket/tst-cmsghdr-skeleton.c
Normal file
92
socket/tst-cmsghdr-skeleton.c
Normal file
@ -0,0 +1,92 @@
|
||||
/* Test ancillary data header creation.
|
||||
Copyright (C) 2022 Free Software Foundation, Inc.
|
||||
This file is part of the GNU C Library.
|
||||
|
||||
The GNU C Library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
License as published by the Free Software Foundation; either
|
||||
version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
The GNU C Library is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public
|
||||
License along with the GNU C Library; if not, see
|
||||
<https://www.gnu.org/licenses/>. */
|
||||
|
||||
/* We use the preprocessor to generate the function/macro tests instead of
|
||||
using indirection because having all the macro expansions alongside
|
||||
each other lets the compiler warn us about suspicious pointer
|
||||
arithmetic across subsequent CMSG_{FIRST,NXT}HDR expansions. */
|
||||
|
||||
#include <stdint.h>
|
||||
|
||||
#define RUN_TEST_CONCAT(suffix) run_test_##suffix
|
||||
#define RUN_TEST_FUNCNAME(suffix) RUN_TEST_CONCAT (suffix)
|
||||
|
||||
static void
|
||||
RUN_TEST_FUNCNAME (CMSG_NXTHDR_IMPL) (void)
|
||||
{
|
||||
struct msghdr m = {0};
|
||||
struct cmsghdr *cmsg;
|
||||
char cmsgbuf[3 * CMSG_SPACE (sizeof (PAYLOAD))] = {0};
|
||||
|
||||
m.msg_control = cmsgbuf;
|
||||
m.msg_controllen = sizeof (cmsgbuf);
|
||||
|
||||
/* First header should point to the start of the buffer. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
|
||||
/* If the first header length consumes the entire buffer, there is no
|
||||
space remaining for additional headers. */
|
||||
cmsg->cmsg_len = sizeof (cmsgbuf);
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg == NULL);
|
||||
|
||||
/* The first header length is so big, using it would cause an overflow. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
cmsg->cmsg_len = SIZE_MAX;
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg == NULL);
|
||||
|
||||
/* The first header leaves just enough space to hold another header. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
cmsg->cmsg_len = sizeof (cmsgbuf) - sizeof (struct cmsghdr);
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg != NULL);
|
||||
|
||||
/* The first header leaves space but not enough for another header. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
cmsg->cmsg_len ++;
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg == NULL);
|
||||
|
||||
/* The second header leaves just enough space to hold another header. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
cmsg->cmsg_len = CMSG_LEN (sizeof (PAYLOAD));
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg != NULL);
|
||||
cmsg->cmsg_len = sizeof (cmsgbuf)
|
||||
- CMSG_SPACE (sizeof (PAYLOAD)) /* First header. */
|
||||
- sizeof (struct cmsghdr);
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg != NULL);
|
||||
|
||||
/* The second header leaves space but not enough for another header. */
|
||||
cmsg = CMSG_FIRSTHDR (&m);
|
||||
TEST_VERIFY_EXIT ((char *) cmsg == cmsgbuf);
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg != NULL);
|
||||
cmsg->cmsg_len ++;
|
||||
cmsg = CMSG_NXTHDR_IMPL (&m, cmsg);
|
||||
TEST_VERIFY_EXIT (cmsg == NULL);
|
||||
|
||||
return;
|
||||
}
|
56
socket/tst-cmsghdr.c
Normal file
56
socket/tst-cmsghdr.c
Normal file
@ -0,0 +1,56 @@
|
||||
/* Test ancillary data header creation.
|
||||
Copyright (C) 2022 Free Software Foundation, Inc.
|
||||
This file is part of the GNU C Library.
|
||||
|
||||
The GNU C Library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
License as published by the Free Software Foundation; either
|
||||
version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
The GNU C Library is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public
|
||||
License along with the GNU C Library; if not, see
|
||||
<https://www.gnu.org/licenses/>. */
|
||||
|
||||
#include <sys/socket.h>
|
||||
#include <gnu/lib-names.h>
|
||||
#include <support/xdlfcn.h>
|
||||
#include <support/check.h>
|
||||
|
||||
#define PAYLOAD "Hello, World!"
|
||||
|
||||
/* CMSG_NXTHDR is a macro that calls an inline function defined in
|
||||
bits/socket.h. In case the function cannot be inlined, libc.so carries
|
||||
a copy. Both versions need to be tested. */
|
||||
|
||||
#define CMSG_NXTHDR_IMPL CMSG_NXTHDR
|
||||
#include "tst-cmsghdr-skeleton.c"
|
||||
#undef CMSG_NXTHDR_IMPL
|
||||
|
||||
static struct cmsghdr * (* cmsg_nxthdr) (struct msghdr *, struct cmsghdr *);
|
||||
|
||||
#define CMSG_NXTHDR_IMPL cmsg_nxthdr
|
||||
#include "tst-cmsghdr-skeleton.c"
|
||||
#undef CMSG_NXTHDR_IMPL
|
||||
|
||||
static int
|
||||
do_test (void)
|
||||
{
|
||||
static void *handle;
|
||||
|
||||
run_test_CMSG_NXTHDR ();
|
||||
|
||||
handle = xdlopen (LIBC_SO, RTLD_LAZY);
|
||||
cmsg_nxthdr = (struct cmsghdr * (*) (struct msghdr *, struct cmsghdr *))
|
||||
xdlsym (handle, "__cmsg_nxthdr");
|
||||
|
||||
run_test_cmsg_nxthdr ();
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
#include <support/test-driver.c>
|
@ -249,6 +249,12 @@ struct cmsghdr
|
||||
+ CMSG_ALIGN (sizeof (struct cmsghdr)))
|
||||
#define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
|
||||
|
||||
/* Given a length, return the additional padding necessary such that
|
||||
len + __CMSG_PADDING(len) == CMSG_ALIGN (len). */
|
||||
#define __CMSG_PADDING(len) ((sizeof (size_t) \
|
||||
- ((len) & (sizeof (size_t) - 1))) \
|
||||
& (sizeof (size_t) - 1))
|
||||
|
||||
extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
struct cmsghdr *__cmsg) __THROW;
|
||||
#ifdef __USE_EXTERN_INLINES
|
||||
@ -258,18 +264,38 @@ extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
_EXTERN_INLINE struct cmsghdr *
|
||||
__NTH (__cmsg_nxthdr (struct msghdr *__mhdr, struct cmsghdr *__cmsg))
|
||||
{
|
||||
/* We may safely assume that __cmsg lies between __mhdr->msg_control and
|
||||
__mhdr->msg_controllen because the user is required to obtain the first
|
||||
cmsg via CMSG_FIRSTHDR, set its length, then obtain subsequent cmsgs
|
||||
via CMSG_NXTHDR, setting lengths along the way. However, we don't yet
|
||||
trust the value of __cmsg->cmsg_len and therefore do not use it in any
|
||||
pointer arithmetic until we check its value. */
|
||||
|
||||
unsigned char * __msg_control_ptr = (unsigned char *) __mhdr->msg_control;
|
||||
unsigned char * __cmsg_ptr = (unsigned char *) __cmsg;
|
||||
|
||||
size_t __size_needed = sizeof (struct cmsghdr)
|
||||
+ __CMSG_PADDING (__cmsg->cmsg_len);
|
||||
|
||||
/* The current header is malformed, too small to be a full header. */
|
||||
if ((size_t) __cmsg->cmsg_len < sizeof (struct cmsghdr))
|
||||
/* The kernel header does this so there may be a reason. */
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* There isn't enough space between __cmsg and the end of the buffer to
|
||||
hold the current cmsg *and* the next one. */
|
||||
if (((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr)
|
||||
< __size_needed)
|
||||
|| ((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr
|
||||
- __size_needed)
|
||||
< __cmsg->cmsg_len))
|
||||
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* Now, we trust cmsg_len and can use it to find the next header. */
|
||||
__cmsg = (struct cmsghdr *) ((unsigned char *) __cmsg
|
||||
+ CMSG_ALIGN (__cmsg->cmsg_len));
|
||||
if ((unsigned char *) (__cmsg + 1) > ((unsigned char *) __mhdr->msg_control
|
||||
+ __mhdr->msg_controllen)
|
||||
|| ((unsigned char *) __cmsg + CMSG_ALIGN (__cmsg->cmsg_len)
|
||||
> ((unsigned char *) __mhdr->msg_control + __mhdr->msg_controllen)))
|
||||
/* No more entries. */
|
||||
return (struct cmsghdr *) 0;
|
||||
return __cmsg;
|
||||
}
|
||||
#endif /* Use `extern inline'. */
|
||||
|
@ -307,6 +307,12 @@ struct cmsghdr
|
||||
+ CMSG_ALIGN (sizeof (struct cmsghdr)))
|
||||
#define CMSG_LEN(len) (CMSG_ALIGN (sizeof (struct cmsghdr)) + (len))
|
||||
|
||||
/* Given a length, return the additional padding necessary such that
|
||||
len + __CMSG_PADDING(len) == CMSG_ALIGN (len). */
|
||||
#define __CMSG_PADDING(len) ((sizeof (size_t) \
|
||||
- ((len) & (sizeof (size_t) - 1))) \
|
||||
& (sizeof (size_t) - 1))
|
||||
|
||||
extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
struct cmsghdr *__cmsg) __THROW;
|
||||
#ifdef __USE_EXTERN_INLINES
|
||||
@ -316,18 +322,38 @@ extern struct cmsghdr *__cmsg_nxthdr (struct msghdr *__mhdr,
|
||||
_EXTERN_INLINE struct cmsghdr *
|
||||
__NTH (__cmsg_nxthdr (struct msghdr *__mhdr, struct cmsghdr *__cmsg))
|
||||
{
|
||||
/* We may safely assume that __cmsg lies between __mhdr->msg_control and
|
||||
__mhdr->msg_controllen because the user is required to obtain the first
|
||||
cmsg via CMSG_FIRSTHDR, set its length, then obtain subsequent cmsgs
|
||||
via CMSG_NXTHDR, setting lengths along the way. However, we don't yet
|
||||
trust the value of __cmsg->cmsg_len and therefore do not use it in any
|
||||
pointer arithmetic until we check its value. */
|
||||
|
||||
unsigned char * __msg_control_ptr = (unsigned char *) __mhdr->msg_control;
|
||||
unsigned char * __cmsg_ptr = (unsigned char *) __cmsg;
|
||||
|
||||
size_t __size_needed = sizeof (struct cmsghdr)
|
||||
+ __CMSG_PADDING (__cmsg->cmsg_len);
|
||||
|
||||
/* The current header is malformed, too small to be a full header. */
|
||||
if ((size_t) __cmsg->cmsg_len < sizeof (struct cmsghdr))
|
||||
/* The kernel header does this so there may be a reason. */
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* There isn't enough space between __cmsg and the end of the buffer to
|
||||
hold the current cmsg *and* the next one. */
|
||||
if (((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr)
|
||||
< __size_needed)
|
||||
|| ((size_t)
|
||||
(__msg_control_ptr + __mhdr->msg_controllen - __cmsg_ptr
|
||||
- __size_needed)
|
||||
< __cmsg->cmsg_len))
|
||||
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* Now, we trust cmsg_len and can use it to find the next header. */
|
||||
__cmsg = (struct cmsghdr *) ((unsigned char *) __cmsg
|
||||
+ CMSG_ALIGN (__cmsg->cmsg_len));
|
||||
if ((unsigned char *) (__cmsg + 1) > ((unsigned char *) __mhdr->msg_control
|
||||
+ __mhdr->msg_controllen)
|
||||
|| ((unsigned char *) __cmsg + CMSG_ALIGN (__cmsg->cmsg_len)
|
||||
> ((unsigned char *) __mhdr->msg_control + __mhdr->msg_controllen)))
|
||||
/* No more entries. */
|
||||
return (struct cmsghdr *) 0;
|
||||
return __cmsg;
|
||||
}
|
||||
#endif /* Use `extern inline'. */
|
||||
|
@ -23,18 +23,38 @@
|
||||
struct cmsghdr *
|
||||
__cmsg_nxthdr (struct msghdr *mhdr, struct cmsghdr *cmsg)
|
||||
{
|
||||
if ((size_t) cmsg->cmsg_len < sizeof (struct cmsghdr))
|
||||
/* The kernel header does this so there may be a reason. */
|
||||
return NULL;
|
||||
/* We may safely assume that cmsg lies between mhdr->msg_control and
|
||||
mhdr->msg_controllen because the user is required to obtain the first
|
||||
cmsg via CMSG_FIRSTHDR, set its length, then obtain subsequent cmsgs
|
||||
via CMSG_NXTHDR, setting lengths along the way. However, we don't yet
|
||||
trust the value of cmsg->cmsg_len and therefore do not use it in any
|
||||
pointer arithmetic until we check its value. */
|
||||
|
||||
unsigned char * msg_control_ptr = (unsigned char *) mhdr->msg_control;
|
||||
unsigned char * cmsg_ptr = (unsigned char *) cmsg;
|
||||
|
||||
size_t size_needed = sizeof (struct cmsghdr)
|
||||
+ __CMSG_PADDING (cmsg->cmsg_len);
|
||||
|
||||
/* The current header is malformed, too small to be a full header. */
|
||||
if ((size_t) cmsg->cmsg_len < sizeof (struct cmsghdr))
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* There isn't enough space between cmsg and the end of the buffer to
|
||||
hold the current cmsg *and* the next one. */
|
||||
if (((size_t)
|
||||
(msg_control_ptr + mhdr->msg_controllen - cmsg_ptr)
|
||||
< size_needed)
|
||||
|| ((size_t)
|
||||
(msg_control_ptr + mhdr->msg_controllen - cmsg_ptr
|
||||
- size_needed)
|
||||
< cmsg->cmsg_len))
|
||||
|
||||
return (struct cmsghdr *) 0;
|
||||
|
||||
/* Now, we trust cmsg_len and can use it to find the next header. */
|
||||
cmsg = (struct cmsghdr *) ((unsigned char *) cmsg
|
||||
+ CMSG_ALIGN (cmsg->cmsg_len));
|
||||
if ((unsigned char *) (cmsg + 1) > ((unsigned char *) mhdr->msg_control
|
||||
+ mhdr->msg_controllen)
|
||||
|| ((unsigned char *) cmsg + CMSG_ALIGN (cmsg->cmsg_len)
|
||||
> ((unsigned char *) mhdr->msg_control + mhdr->msg_controllen)))
|
||||
/* No more entries. */
|
||||
return NULL;
|
||||
return cmsg;
|
||||
}
|
||||
libc_hidden_def (__cmsg_nxthdr)
|
||||
|
Loading…
Reference in New Issue
Block a user