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3a15e92ce7
sssd/0001-Validate-user-supplied-size-of-data-items.patch

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From 3e20a867ca16c54ee788bdaf854b612f9c8618a2 Mon Sep 17 00:00:00 2001
From: Sumit Bose <sbose@redhat.com>
Date: Mon, 6 Dec 2010 21:18:50 +0100
Subject: [PATCH] Validate user supplied size of data items
Specially crafted packages might lead to an integer overflow and the
parsing of the input buffer might not continue as expected. This issue
was identified by Sebastian Krahmer <krahmer@suse.de>.
Add overflow check to SAFEALIGN_COPY_*_CHECK macros
---
src/responder/pam/pamsrv_cmd.c | 147 ++++++++++++++++++++--------------------
src/tests/util-tests.c | 14 ++++
src/util/util.h | 14 +++-
3 files changed, 98 insertions(+), 77 deletions(-)
diff --git a/src/responder/pam/pamsrv_cmd.c b/src/responder/pam/pamsrv_cmd.c
index 6a8f1dbb515c63125c810dca15ac186c58b1bafb..bb42f712399dedb01535b1347d096b5e02543dbc 100644
--- a/src/responder/pam/pamsrv_cmd.c
+++ b/src/responder/pam/pamsrv_cmd.c
@@ -42,18 +42,15 @@ enum pam_verbosity {
static void pam_reply(struct pam_auth_req *preq);
-static int extract_authtok(uint32_t *type, uint32_t *size, uint8_t **tok, uint8_t *body, size_t blen, size_t *c) {
- uint32_t data_size;
+static int extract_authtok(uint32_t *type, uint32_t *size, uint8_t **tok,
+ size_t data_size, uint8_t *body, size_t blen,
+ size_t *c) {
- if (blen-(*c) < 2*sizeof(uint32_t)) return EINVAL;
-
- memcpy(&data_size, &body[*c], sizeof(uint32_t));
- *c += sizeof(uint32_t);
- if (data_size < sizeof(uint32_t) || (*c)+(data_size) > blen) return EINVAL;
+ if (data_size < sizeof(uint32_t) || *c+data_size > blen ||
+ SIZE_T_OVERFLOW(*c, data_size)) return EINVAL;
*size = data_size - sizeof(uint32_t);
- memcpy(type, &body[*c], sizeof(uint32_t));
- *c += sizeof(uint32_t);
+ SAFEALIGN_COPY_UINT32_CHECK(type, &body[*c], blen, c);
*tok = body+(*c);
@@ -62,15 +59,11 @@ static int extract_authtok(uint32_t *type, uint32_t *size, uint8_t **tok, uint8_
return EOK;
}
-static int extract_string(char **var, uint8_t *body, size_t blen, size_t *c) {
- uint32_t size;
+static int extract_string(char **var, size_t size, uint8_t *body, size_t blen,
+ size_t *c) {
uint8_t *str;
- if (blen-(*c) < sizeof(uint32_t)+1) return EINVAL;
-
- memcpy(&size, &body[*c], sizeof(uint32_t));
- *c += sizeof(uint32_t);
- if (*c+size > blen) return EINVAL;
+ if (*c+size > blen || SIZE_T_OVERFLOW(*c, size)) return EINVAL;
str = body+(*c);
@@ -83,16 +76,13 @@ static int extract_string(char **var, uint8_t *body, size_t blen, size_t *c) {
return EOK;
}
-static int extract_uint32_t(uint32_t *var, uint8_t *body, size_t blen, size_t *c) {
- uint32_t size;
+static int extract_uint32_t(uint32_t *var, size_t size, uint8_t *body,
+ size_t blen, size_t *c) {
- if (blen-(*c) < 2*sizeof(uint32_t)) return EINVAL;
+ if (size != sizeof(uint32_t) || *c+size > blen || SIZE_T_OVERFLOW(*c, size))
+ return EINVAL;
- memcpy(&size, &body[*c], sizeof(uint32_t));
- *c += sizeof(uint32_t);
-
- memcpy(var, &body[*c], sizeof(uint32_t));
- *c += sizeof(uint32_t);
+ SAFEALIGN_COPY_UINT32_CHECK(var, &body[*c], blen, c);
return EOK;
}
@@ -117,59 +107,66 @@ static int pam_parse_in_data_v2(struct sss_names_ctx *snctx,
c = sizeof(uint32_t);
do {
- memcpy(&type, &body[c], sizeof(uint32_t));
- c += sizeof(uint32_t);
- if (c > blen) return EINVAL;
+ SAFEALIGN_COPY_UINT32_CHECK(&type, &body[c], blen, &c);
- switch(type) {
- case SSS_PAM_ITEM_USER:
- ret = extract_string(&pam_user, body, blen, &c);
- if (ret != EOK) return ret;
+ if (type == SSS_END_OF_PAM_REQUEST) {
+ if (c != blen) return EINVAL;
+ } else {
+ SAFEALIGN_COPY_UINT32_CHECK(&size, &body[c], blen, &c);
+ /* the uint32_t end maker SSS_END_OF_PAM_REQUEST does not count to
+ * the remaining buffer */
+ if (size > (blen - c - sizeof(uint32_t))) {
+ DEBUG(1, ("Invalid data size.\n"));
+ return EINVAL;
+ }
- ret = sss_parse_name(pd, snctx, pam_user,
- &pd->domain, &pd->user);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_SERVICE:
- ret = extract_string(&pd->service, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_TTY:
- ret = extract_string(&pd->tty, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_RUSER:
- ret = extract_string(&pd->ruser, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_RHOST:
- ret = extract_string(&pd->rhost, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_CLI_PID:
- ret = extract_uint32_t(&pd->cli_pid,
- body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_AUTHTOK:
- ret = extract_authtok(&pd->authtok_type, &pd->authtok_size,
- &pd->authtok, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_PAM_ITEM_NEWAUTHTOK:
- ret = extract_authtok(&pd->newauthtok_type,
- &pd->newauthtok_size,
- &pd->newauthtok, body, blen, &c);
- if (ret != EOK) return ret;
- break;
- case SSS_END_OF_PAM_REQUEST:
- if (c != blen) return EINVAL;
- break;
- default:
- DEBUG(1,("Ignoring unknown data type [%d].\n", type));
- size = ((uint32_t *)&body[c])[0];
- c += size+sizeof(uint32_t);
+ switch(type) {
+ case SSS_PAM_ITEM_USER:
+ ret = extract_string(&pam_user, size, body, blen, &c);
+ if (ret != EOK) return ret;
+
+ ret = sss_parse_name(pd, snctx, pam_user,
+ &pd->domain, &pd->user);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_SERVICE:
+ ret = extract_string(&pd->service, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_TTY:
+ ret = extract_string(&pd->tty, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_RUSER:
+ ret = extract_string(&pd->ruser, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_RHOST:
+ ret = extract_string(&pd->rhost, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_CLI_PID:
+ ret = extract_uint32_t(&pd->cli_pid, size,
+ body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_AUTHTOK:
+ ret = extract_authtok(&pd->authtok_type, &pd->authtok_size,
+ &pd->authtok, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ case SSS_PAM_ITEM_NEWAUTHTOK:
+ ret = extract_authtok(&pd->newauthtok_type,
+ &pd->newauthtok_size,
+ &pd->newauthtok, size, body, blen, &c);
+ if (ret != EOK) return ret;
+ break;
+ default:
+ DEBUG(1,("Ignoring unknown data type [%d].\n", type));
+ c += size;
+ }
}
+
} while(c < blen);
if (pd->user == NULL || *pd->user == '\0') return EINVAL;
@@ -240,6 +237,7 @@ static int pam_parse_in_data(struct sss_names_ctx *snctx,
start += sizeof(uint32_t);
pd->authtok_size = (int) body[start];
+ if (pd->authtok_size >= blen) return EINVAL;
start += sizeof(uint32_t);
end = start + pd->authtok_size;
@@ -259,6 +257,7 @@ static int pam_parse_in_data(struct sss_names_ctx *snctx,
start += sizeof(uint32_t);
pd->newauthtok_size = (int) body[start];
+ if (pd->newauthtok_size >= blen) return EINVAL;
start += sizeof(uint32_t);
end = start + pd->newauthtok_size;
diff --git a/src/tests/util-tests.c b/src/tests/util-tests.c
index cf96f0e356942c2bcd2667a2b778a65a91f46e2d..a98b0c03c8119c2c54df4feecb03e221325b30e7 100644
--- a/src/tests/util-tests.c
+++ b/src/tests/util-tests.c
@@ -241,6 +241,19 @@ START_TEST(test_sss_filter_sanitize)
}
END_TEST
+START_TEST(test_size_t_overflow)
+{
+ fail_unless(!SIZE_T_OVERFLOW(1, 1), "unexpected overflow");
+ fail_unless(!SIZE_T_OVERFLOW(SIZE_T_MAX, 0), "unexpected overflow");
+ fail_unless(!SIZE_T_OVERFLOW(SIZE_T_MAX-10, 10), "unexpected overflow");
+ fail_unless(SIZE_T_OVERFLOW(SIZE_T_MAX, 1), "overflow not detected");
+ fail_unless(SIZE_T_OVERFLOW(SIZE_T_MAX, SIZE_T_MAX),
+ "overflow not detected");
+ fail_unless(SIZE_T_OVERFLOW(SIZE_T_MAX, ULLONG_MAX),
+ "overflow not detected");
+ fail_unless(SIZE_T_OVERFLOW(SIZE_T_MAX, -10), "overflow not detected");
+}
+END_TEST
Suite *util_suite(void)
{
@@ -250,6 +263,7 @@ Suite *util_suite(void)
tcase_add_test (tc_util, test_diff_string_lists);
tcase_add_test (tc_util, test_sss_filter_sanitize);
+ tcase_add_test (tc_util, test_size_t_overflow);
tcase_set_timeout(tc_util, 60);
suite_add_tcase (s, tc_util);
diff --git a/src/util/util.h b/src/util/util.h
index f1e11a847b036b937098babed8e28740720b4763..61fe7f6c24c4c1673baf4789f4d76ae76eb25970 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -171,6 +171,11 @@ errno_t set_debug_file_from_fd(const int fd);
#define OUT_OF_ID_RANGE(id, min, max) \
(id == 0 || (min && (id < min)) || (max && (id > max)))
+#define SIZE_T_MAX ((size_t) -1)
+
+#define SIZE_T_OVERFLOW(current, add) \
+ (((size_t)(add)) > (SIZE_T_MAX - ((size_t)(current))))
+
static inline void
safealign_memcpy(void *dest, const void *src, size_t n, size_t *counter)
{
@@ -210,17 +215,20 @@ safealign_memcpy(void *dest, const void *src, size_t n, size_t *counter)
SAFEALIGN_SET_VALUE(dest, value, uint16_t, pctr)
#define SAFEALIGN_COPY_UINT32_CHECK(dest, src, len, pctr) do { \
- if ((*(pctr) + sizeof(uint32_t)) > (len)) return EINVAL; \
+ if ((*(pctr) + sizeof(uint32_t)) > (len) || \
+ SIZE_T_OVERFLOW(*(pctr), sizeof(uint32_t))) return EINVAL; \
safealign_memcpy(dest, src, sizeof(uint32_t), pctr); \
} while(0)
#define SAFEALIGN_COPY_INT32_CHECK(dest, src, len, pctr) do { \
- if ((*(pctr) + sizeof(int32_t)) > (len)) return EINVAL; \
+ if ((*(pctr) + sizeof(int32_t)) > (len) || \
+ SIZE_T_OVERFLOW(*(pctr), sizeof(int32_t))) return EINVAL; \
safealign_memcpy(dest, src, sizeof(int32_t), pctr); \
} while(0)
#define SAFEALIGN_COPY_UINT16_CHECK(dest, src, len, pctr) do { \
- if ((*(pctr) + sizeof(uint16_t)) > (len)) return EINVAL; \
+ if ((*(pctr) + sizeof(uint16_t)) > (len) || \
+ SIZE_T_OVERFLOW(*(pctr), sizeof(uint16_t))) return EINVAL; \
safealign_memcpy(dest, src, sizeof(uint16_t), pctr); \
} while(0)
--
1.7.3.4
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