diff options
Diffstat (limited to 'poky/meta/recipes-devtools/qemu/qemu/CVE-2020-13253_2.patch')
| -rw-r--r-- | poky/meta/recipes-devtools/qemu/qemu/CVE-2020-13253_2.patch | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-13253_2.patch b/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-13253_2.patch new file mode 100644 index 0000000000..53145d059f --- /dev/null +++ b/poky/meta/recipes-devtools/qemu/qemu/CVE-2020-13253_2.patch @@ -0,0 +1,112 @@ +From a9bcedd15a5834ca9ae6c3a97933e85ac7edbd36 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org> +Date: Tue, 7 Jul 2020 13:02:34 +0200 +Subject: [PATCH] hw/sd/sdcard: Do not allow invalid SD card sizes +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +QEMU allows to create SD card with unrealistic sizes. This could +work, but some guests (at least Linux) consider sizes that are not +a power of 2 as a firmware bug and fix the card size to the next +power of 2. + +While the possibility to use small SD card images has been seen as +a feature, it became a bug with CVE-2020-13253, where the guest is +able to do OOB read/write accesses past the image size end. + +In a pair of commits we will fix CVE-2020-13253 as: + + Read command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR + occurred and no data transfer is performed. + + Write command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR + occurred and no data transfer is performed. + + WP_VIOLATION errors are not modified: the error bit is set, we + stay in receive-data state, wait for a stop command. All further + data transfer is ignored. See the check on sd->card_status at the + beginning of sd_read_data() and sd_write_data(). + +While this is the correct behavior, in case QEMU create smaller SD +cards, guests still try to access past the image size end, and QEMU +considers this is an invalid address, thus "all further data transfer +is ignored". This is wrong and make the guest looping until +eventually timeouts. + +Fix by not allowing invalid SD card sizes (suggesting the expected +size as a hint): + + $ qemu-system-arm -M orangepi-pc -drive file=rootfs.ext2,if=sd,format=raw + qemu-system-arm: Invalid SD card size: 60 MiB + SD card size has to be a power of 2, e.g. 64 MiB. + You can resize disk images with 'qemu-img resize <imagefile> <new-size>' + (note that this will lose data if you make the image smaller than it currently is). + +Cc: qemu-stable@nongnu.org +Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> +Reviewed-by: Alistair Francis <alistair.francis@wdc.com> +Reviewed-by: Peter Maydell <peter.maydell@linaro.org> +Message-Id: <20200713183209.26308-8-f4bug@amsat.org> + +Upstram-Status: Backport: +https://git.qemu.org/?p=qemu.git;a=commit;h=a9bcedd15a5834ca9ae6c3a97933e85ac7edbd36 + +CVE: CVE-2020-13253 + +Signed-off-by: Davide Gardenal <davide.gardenal@huawei.com> +--- + hw/sd/sd.c | 25 +++++++++++++++++++++++++ + 1 file changed, 25 insertions(+) + +diff --git a/hw/sd/sd.c b/hw/sd/sd.c +index edd60a09c0..76d68359a4 100644 +--- a/hw/sd/sd.c ++++ b/hw/sd/sd.c +@@ -32,6 +32,7 @@ + + #include "qemu/osdep.h" + #include "qemu/units.h" ++#include "qemu/cutils.h" + #include "hw/irq.h" + #include "hw/registerfields.h" + #include "sysemu/block-backend.h" +@@ -2106,11 +2107,35 @@ static void sd_realize(DeviceState *dev, Error **errp) + } + + if (sd->blk) { ++ int64_t blk_size; ++ + if (blk_is_read_only(sd->blk)) { + error_setg(errp, "Cannot use read-only drive as SD card"); + return; + } + ++ blk_size = blk_getlength(sd->blk); ++ if (blk_size > 0 && !is_power_of_2(blk_size)) { ++ int64_t blk_size_aligned = pow2ceil(blk_size); ++ char *blk_size_str; ++ ++ blk_size_str = size_to_str(blk_size); ++ error_setg(errp, "Invalid SD card size: %s", blk_size_str); ++ g_free(blk_size_str); ++ ++ blk_size_str = size_to_str(blk_size_aligned); ++ error_append_hint(errp, ++ "SD card size has to be a power of 2, e.g. %s.\n" ++ "You can resize disk images with" ++ " 'qemu-img resize <imagefile> <new-size>'\n" ++ "(note that this will lose data if you make the" ++ " image smaller than it currently is).\n", ++ blk_size_str); ++ g_free(blk_size_str); ++ ++ return; ++ } ++ + ret = blk_set_perm(sd->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE, + BLK_PERM_ALL, errp); + if (ret < 0) { +-- +2.32.0 + |