git: f350bc1dd368 - main - ada: Fix intra-object buffer overread of identify strings

The branch main has been updated by jrtc27:

URL: https://cgit.FreeBSD.org/src/commit/?id=f350bc1dd368a3024ba9ef2a9e8431fc1edd8094

commit f350bc1dd368a3024ba9ef2a9e8431fc1edd8094
Author:     Jessica Clarke <jrtc27@FreeBSD.org>
AuthorDate: 2021-10-24 18:48:59 +0000
Commit:     Jessica Clarke <jrtc27@FreeBSD.org>
CommitDate: 2021-10-27 17:38:37 +0000

    ada: Fix intra-object buffer overread of identify strings
    
    In the ATA/ATAPI spec these are space-padded fixed-length strings with
    no NUL-terminator (and byte swapped). When performing the identify we
    call ata_param_fixup to swap the bytes back to be in order, strip any
    leading/trailing spaces and coalesce consecutive spaces, padding with
    NULs. However, if the input has no padding spaces, the fixed-up strings
    are still not NUL-terminated. This causes two issues. The first is that
    strlcpy will truncate the string by replacing the final byte with a NUL.
    The second is that strlcpy will keep reading src until it finds a NUL in
    order to calculate the return value, which is defined as the length of
    src (so that callers can then compare it with the dsize input to see if
    the input string was truncated), thereby reading past the end of the
    buffer and into whatever adjacent fields are in the structure. In
    practice there's a NUL byte somewhere in the structure, but on CHERI
    with subobject bounds enabled in the compiler this overread will be
    detected and trap as a bounds violation.
    
    Note this matches ata_xpt's aprobedone, which does a bcopy to a
    malloc'ed buffer and manually NUL-terminates it for the CAM path's
    device's serial_num.
    
    Found by:       CHERI
    Reviewed by:    imp, scottl
    Differential Revision:  https://reviews.freebsd.org/D32567
---
 sys/cam/ata/ata_da.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/sys/cam/ata/ata_da.c b/sys/cam/ata/ata_da.c
index 72bbbfe8ab1f..c05a9fa49d1c 100644
--- a/sys/cam/ata/ata_da.c
+++ b/sys/cam/ata/ata_da.c
@@ -3424,6 +3424,7 @@ adasetgeom(struct ada_softc *softc, struct ccb_getdev *cgd)
 	u_int64_t lbasize48;
 	u_int32_t lbasize;
 	u_int maxio, d_flags;
+	size_t tmpsize;
 
 	dp->secsize = ata_logical_sector_size(&cgd->ident_data);
 	if ((cgd->ident_data.atavalid & ATA_FLAG_54_58) &&
@@ -3487,10 +3488,25 @@ adasetgeom(struct ada_softc *softc, struct ccb_getdev *cgd)
 		softc->flags |= ADA_FLAG_UNMAPPEDIO;
 	}
 	softc->disk->d_flags = d_flags;
-	strlcpy(softc->disk->d_descr, cgd->ident_data.model,
-	    MIN(sizeof(softc->disk->d_descr), sizeof(cgd->ident_data.model)));
-	strlcpy(softc->disk->d_ident, cgd->ident_data.serial,
-	    MIN(sizeof(softc->disk->d_ident), sizeof(cgd->ident_data.serial)));
+
+	/*
+	 * ata_param_fixup will strip trailing padding spaces and add a NUL,
+	 * but if the field has no padding (as is common for serial numbers)
+	 * there will still be no NUL terminator. We cannot use strlcpy, since
+	 * it keeps reading src until it finds a NUL in order to compute the
+	 * return value (and will truncate the final character due to having a
+	 * single dsize rather than separate ssize and dsize), and strncpy does
+	 * not add a NUL to the destination if it reaches the character limit.
+	 */
+	tmpsize = MIN(sizeof(softc->disk->d_descr) - 1,
+	    sizeof(cgd->ident_data.model));
+	memcpy(softc->disk->d_descr, cgd->ident_data.model, tmpsize);
+	softc->disk->d_descr[tmpsize] = '\0';
+
+	tmpsize = MIN(sizeof(softc->disk->d_ident) - 1,
+	    sizeof(cgd->ident_data.serial));
+	memcpy(softc->disk->d_ident, cgd->ident_data.serial, tmpsize);
+	softc->disk->d_ident[tmpsize] = '\0';
 
 	softc->disk->d_sectorsize = softc->params.secsize;
 	softc->disk->d_mediasize = (off_t)softc->params.sectors *