mpr/mps/mpt: verify cfg page ioctl lengths

*_CFG_PAGE ioctl handlers in the mpr, mps, and mpt drivers allocated a
buffer of a caller-specified size, but copied to it a fixed size header.
Add checks that the size is at least the required minimum.

Note that the device nodes are owned by root:operator with 0640
permissions so the ioctls are not available to unprivileged users.

This change includes suggestions from scottl, markj and mav.

Two of the mpt cases were reported by Lucas Leong (@_wmliang_) of
Trend Micro Zero Day Initiative; scottl reported the third case in mpt.
Same issue found in mpr and mps after discussion with imp.

Reported by:	Lucas Leong (@_wmliang_), Trend Micro Zero Day Initiative
Reviewed by:	imp, mav
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D34692

(cherry picked from commit 8276c4149b5fc7c755d6b244fbbf6dae1939f087)

3 files changed, 39 insertions, 0 deletions

diff --git a/sys/dev/mpr/mpr_user.c b/sys/dev/mpr/mpr_user.c
index cab865e2e535..08c2b8b39244 100644
--- a/sys/dev/mpr/mpr_user.c
+++ b/sys/dev/mpr/mpr_user.c
@@ -2266,6 +2266,10 @@ mpr_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		mpr_unlock(sc);
 		break;
 	case MPRIO_READ_CFG_PAGE:
+		if (page_req->len < (int)sizeof(MPI2_CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mpr_page = malloc(page_req->len, M_MPRUSER, M_WAITOK | M_ZERO);
 		error = copyin(page_req->buf, mpr_page,
 		    sizeof(MPI2_CONFIG_PAGE_HEADER));
@@ -2284,6 +2288,11 @@ mpr_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		mpr_unlock(sc);
 		break;
 	case MPRIO_READ_EXT_CFG_PAGE:
+		if (ext_page_req->len <
+		    (int)sizeof(MPI2_CONFIG_EXTENDED_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mpr_page = malloc(ext_page_req->len, M_MPRUSER,
 		    M_WAITOK | M_ZERO);
 		error = copyin(ext_page_req->buf, mpr_page,
@@ -2298,6 +2307,10 @@ mpr_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		error = copyout(mpr_page, ext_page_req->buf, ext_page_req->len);
 		break;
 	case MPRIO_WRITE_CFG_PAGE:
+		if (page_req->len < (int)sizeof(MPI2_CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mpr_page = malloc(page_req->len, M_MPRUSER, M_WAITOK|M_ZERO);
 		error = copyin(page_req->buf, mpr_page, page_req->len);
 		if (error)
diff --git a/sys/dev/mps/mps_user.c b/sys/dev/mps/mps_user.c
index 9d4aab54562f..a16201cde131 100644
--- a/sys/dev/mps/mps_user.c
+++ b/sys/dev/mps/mps_user.c
@@ -2168,6 +2168,10 @@ mps_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		mps_unlock(sc);
 		break;
 	case MPSIO_READ_CFG_PAGE:
+		if (page_req->len < (int)sizeof(MPI2_CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mps_page = malloc(page_req->len, M_MPSUSER, M_WAITOK | M_ZERO);
 		error = copyin(page_req->buf, mps_page,
 		    sizeof(MPI2_CONFIG_PAGE_HEADER));
@@ -2186,6 +2190,11 @@ mps_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		mps_unlock(sc);
 		break;
 	case MPSIO_READ_EXT_CFG_PAGE:
+		if (ext_page_req->len <
+		    (int)sizeof(MPI2_CONFIG_EXTENDED_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mps_page = malloc(ext_page_req->len, M_MPSUSER, M_WAITOK|M_ZERO);
 		error = copyin(ext_page_req->buf, mps_page,
 		    sizeof(MPI2_CONFIG_EXTENDED_PAGE_HEADER));
@@ -2199,6 +2208,10 @@ mps_ioctl(struct cdev *dev, u_long cmd, void *arg, int flag,
 		error = copyout(mps_page, ext_page_req->buf, ext_page_req->len);
 		break;
 	case MPSIO_WRITE_CFG_PAGE:
+		if (page_req->len < (int)sizeof(MPI2_CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		mps_page = malloc(page_req->len, M_MPSUSER, M_WAITOK|M_ZERO);
 		error = copyin(page_req->buf, mps_page, page_req->len);
 		if (error)
diff --git a/sys/dev/mpt/mpt_user.c b/sys/dev/mpt/mpt_user.c
index cf339387c10e..10d5bac15d49 100644
--- a/sys/dev/mpt/mpt_user.c
+++ b/sys/dev/mpt/mpt_user.c
@@ -672,6 +672,10 @@ mpt_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int flag, struct thread *td
 	case MPTIO_READ_CFG_PAGE32:
 #endif
 	case MPTIO_READ_CFG_PAGE:
+		if (page_req->len < (int)sizeof(CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		error = mpt_alloc_buffer(mpt, &mpt_page, page_req->len);
 		if (error)
 			break;
@@ -698,6 +702,11 @@ mpt_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int flag, struct thread *td
 	case MPTIO_READ_EXT_CFG_PAGE32:
 #endif
 	case MPTIO_READ_EXT_CFG_PAGE:
+		if (ext_page_req->len <
+		    (int)sizeof(CONFIG_EXTENDED_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		error = mpt_alloc_buffer(mpt, &mpt_page, ext_page_req->len);
 		if (error)
 			break;
@@ -717,6 +726,10 @@ mpt_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int flag, struct thread *td
 	case MPTIO_WRITE_CFG_PAGE32:
 #endif
 	case MPTIO_WRITE_CFG_PAGE:
+		if (page_req->len < (int)sizeof(CONFIG_PAGE_HEADER)) {
+			error = EINVAL;
+			break;
+		}
 		error = mpt_alloc_buffer(mpt, &mpt_page, page_req->len);
 		if (error)
 			break;