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authorChristophe de Dinechin <dinechin@redhat.com>2020-02-28 16:00:59 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2020-03-16 22:07:24 +0100
commit4ce1e15fbc7266a108a7c77a3962644b3935346e (patch)
tree998aa0959cb0af451b86aacea5b81a7a64bab538
parenta98135f727595382e200d04c2996e868b7925a01 (diff)
scsi/qemu-pr-helper: Fix out-of-bounds access to trnptid_list[]
Compile error reported by gcc 10.0.1: scsi/qemu-pr-helper.c: In function ‘multipath_pr_out’: scsi/qemu-pr-helper.c:523:32: error: array subscript <unknown> is outside array bounds of ‘struct transportid *[0]’ [-Werror=array-bounds] 523 | paramp.trnptid_list[paramp.num_transportid++] = id; | ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from scsi/qemu-pr-helper.c:36: /usr/include/mpath_persist.h:168:22: note: while referencing ‘trnptid_list’ 168 | struct transportid *trnptid_list[]; | ^~~~~~~~~~~~ scsi/qemu-pr-helper.c:424:35: note: defined here ‘paramp’ 424 | struct prout_param_descriptor paramp; | ^~~~~~ This highlights an actual implementation issue in function multipath_pr_out. The variable paramp is declared with type `struct prout_param_descriptor`, which is a struct terminated by an empty array in mpath_persist.h: struct transportid *trnptid_list[]; That empty array was filled with code that looked like that: trnptid_list[paramp.descr.num_transportid++] = id; This is an actual out-of-bounds access. The fix is to malloc `paramp`. Signed-off-by: Christophe de Dinechin <dinechin@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--scsi/qemu-pr-helper.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
index 0659ceef09..181ed4a186 100644
--- a/scsi/qemu-pr-helper.c
+++ b/scsi/qemu-pr-helper.c
@@ -421,10 +421,13 @@ static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
int rq_servact = cdb[1];
int rq_scope = cdb[2] >> 4;
int rq_type = cdb[2] & 0xf;
- struct prout_param_descriptor paramp;
+ g_autofree struct prout_param_descriptor *paramp = NULL;
char transportids[PR_HELPER_DATA_SIZE];
int r;
+ paramp = g_malloc0(sizeof(struct prout_param_descriptor)
+ + sizeof(struct transportid *) * MPATH_MX_TIDS);
+
if (sz < PR_OUT_FIXED_PARAM_SIZE) {
/* Illegal request, Parameter list length error. This isn't fatal;
* we have read the data, send an error without closing the socket.
@@ -454,10 +457,9 @@ static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
* used by libmpathpersist (which, of course, will immediately
* do the opposite).
*/
- memset(&paramp, 0, sizeof(paramp));
- memcpy(&paramp.key, &param[0], 8);
- memcpy(&paramp.sa_key, &param[8], 8);
- paramp.sa_flags = param[20];
+ memcpy(&paramp->key, &param[0], 8);
+ memcpy(&paramp->sa_key, &param[8], 8);
+ paramp->sa_flags = param[20];
if (sz > PR_OUT_FIXED_PARAM_SIZE) {
size_t transportid_len;
int i, j;
@@ -520,12 +522,13 @@ static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
return CHECK_CONDITION;
}
- paramp.trnptid_list[paramp.num_transportid++] = id;
+ assert(paramp->num_transportid < MPATH_MX_TIDS);
+ paramp->trnptid_list[paramp->num_transportid++] = id;
}
}
r = mpath_persistent_reserve_out(fd, rq_servact, rq_scope, rq_type,
- &paramp, noisy, verbose);
+ paramp, noisy, verbose);
return mpath_reconstruct_sense(fd, r, sense);
}
#endif