From 8c0ecc91b57f8f53b57b3646b61d0ff60a8054b7 Mon Sep 17 00:00:00 2001 From: Fabrice Fontaine Date: Sun, 1 Mar 2020 18:45:29 +0100 Subject: [PATCH] package/blktrace: fix CVE-2018-10689 blktrace (aka Block IO Tracing) 1.2.0, as used with the Linux kernel and Android, has a buffer overflow in the dev_map_read function in btt/devmap.c because the device and devno arrays are too small, as demonstrated by an invalid free when using the btt program with a crafted file. Signed-off-by: Fabrice Fontaine Signed-off-by: Yann E. MORIN --- ...devno-use-PATH_MAX-to-avoid-overflow.patch | 146 ++++++++++++++++++ package/blktrace/blktrace.mk | 3 + 2 files changed, 149 insertions(+) create mode 100644 package/blktrace/0001-btt-make-device-devno-use-PATH_MAX-to-avoid-overflow.patch diff --git a/package/blktrace/0001-btt-make-device-devno-use-PATH_MAX-to-avoid-overflow.patch b/package/blktrace/0001-btt-make-device-devno-use-PATH_MAX-to-avoid-overflow.patch new file mode 100644 index 0000000000..764410d472 --- /dev/null +++ b/package/blktrace/0001-btt-make-device-devno-use-PATH_MAX-to-avoid-overflow.patch @@ -0,0 +1,146 @@ +From d61ff409cb4dda31386373d706ea0cfb1aaac5b7 Mon Sep 17 00:00:00 2001 +From: Jens Axboe +Date: Wed, 2 May 2018 10:24:17 -0600 +Subject: btt: make device/devno use PATH_MAX to avoid overflow + +Herbo Zhang reports: + +I found a bug in blktrace/btt/devmap.c. The code is just as follows: + +https://git.kernel.org/pub/scm/linux/kernel/git/axboe/blktrace.git/tree/btt/devmap.c?id=8349ad2f2d19422a6241f94ea84d696b21de4757 + + struct devmap { + +struct list_head head; +char device[32], devno[32]; // #1 +}; + +LIST_HEAD(all_devmaps); + +static int dev_map_add(char *line) +{ +struct devmap *dmp; + +if (strstr(line, "Device") != NULL) +return 1; + +dmp = malloc(sizeof(struct devmap)); +if (sscanf(line, "%s %s", dmp->device, dmp->devno) != 2) { //#2 +free(dmp); +return 1; +} + +list_add_tail(&dmp->head, &all_devmaps); +return 0; +} + +int dev_map_read(char *fname) +{ +char line[256]; // #3 +FILE *fp = my_fopen(fname, "r"); + +if (!fp) { +perror(fname); +return 1; +} + +while (fscanf(fp, "%255[a-zA-Z0-9 :.,/_-]\n", line) == 1) { +if (dev_map_add(line)) +break; +} + +fclose(fp); +return 0; +} + + The line length is 256, but the dmp->device, dmp->devno max length +is only 32. We can put strings longer than 32 into dmp->device and +dmp->devno , and then they will be overflowed. + + we can trigger this bug just as follows: + + $ python -c "print 'A'*256" > ./test + $ btt -M ./test + + *** Error in btt': free(): invalid next size (fast): 0x000055ad7349b250 *** + ======= Backtrace: ========= + /lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f7f158ce7e5] + /lib/x86_64-linux-gnu/libc.so.6(+0x7fe0a)[0x7f7f158d6e0a] + /lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f7f158da98c] + btt(+0x32e0)[0x55ad7306f2e0] + btt(+0x2c5f)[0x55ad7306ec5f] + btt(+0x251f)[0x55ad7306e51f] + /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f7f15877830] + btt(+0x26b9)[0x55ad7306e6b9] + ======= Memory map: ======== + 55ad7306c000-55ad7307f000 r-xp 00000000 08:14 3698139 + /usr/bin/btt + 55ad7327e000-55ad7327f000 r--p 00012000 08:14 3698139 + /usr/bin/btt + 55ad7327f000-55ad73280000 rw-p 00013000 08:14 3698139 + /usr/bin/btt + 55ad73280000-55ad73285000 rw-p 00000000 00:00 0 + 55ad7349a000-55ad734bb000 rw-p 00000000 00:00 0 + [heap] + 7f7f10000000-7f7f10021000 rw-p 00000000 00:00 0 + 7f7f10021000-7f7f14000000 ---p 00000000 00:00 0 + 7f7f15640000-7f7f15656000 r-xp 00000000 08:14 14942237 + /lib/x86_64-linux-gnu/libgcc_s.so.1 + 7f7f15656000-7f7f15855000 ---p 00016000 08:14 14942237 + /lib/x86_64-linux-gnu/libgcc_s.so.1 + 7f7f15855000-7f7f15856000 r--p 00015000 08:14 14942237 + /lib/x86_64-linux-gnu/libgcc_s.so.1 + 7f7f15856000-7f7f15857000 rw-p 00016000 08:14 14942237 + /lib/x86_64-linux-gnu/libgcc_s.so.1 + 7f7f15857000-7f7f15a16000 r-xp 00000000 08:14 14948477 + /lib/x86_64-linux-gnu/libc-2.23.so + 7f7f15a16000-7f7f15c16000 ---p 001bf000 08:14 14948477 + /lib/x86_64-linux-gnu/libc-2.23.so + 7f7f15c16000-7f7f15c1a000 r--p 001bf000 08:14 14948477 + /lib/x86_64-linux-gnu/libc-2.23.so + 7f7f15c1a000-7f7f15c1c000 rw-p 001c3000 08:14 14948477 + /lib/x86_64-linux-gnu/libc-2.23.so + 7f7f15c1c000-7f7f15c20000 rw-p 00000000 00:00 0 + 7f7f15c20000-7f7f15c46000 r-xp 00000000 08:14 14948478 + /lib/x86_64-linux-gnu/ld-2.23.so + 7f7f15e16000-7f7f15e19000 rw-p 00000000 00:00 0 + 7f7f15e42000-7f7f15e45000 rw-p 00000000 00:00 0 + 7f7f15e45000-7f7f15e46000 r--p 00025000 08:14 14948478 + /lib/x86_64-linux-gnu/ld-2.23.so + 7f7f15e46000-7f7f15e47000 rw-p 00026000 08:14 14948478 + /lib/x86_64-linux-gnu/ld-2.23.so + 7f7f15e47000-7f7f15e48000 rw-p 00000000 00:00 0 + 7ffdebe5c000-7ffdebe7d000 rw-p 00000000 00:00 0 + [stack] + 7ffdebebc000-7ffdebebe000 r--p 00000000 00:00 0 + [vvar] + 7ffdebebe000-7ffdebec0000 r-xp 00000000 00:00 0 + [vdso] + ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 + [vsyscall] + [1] 6272 abort btt -M test + +Signed-off-by: Jens Axboe +[Retrieved from: +https://git.kernel.org/pub/scm/linux/kernel/git/axboe/blktrace.git/commit/?id=d61ff409cb4dda31386373d706ea0cfb1aaac5b7] +Signed-off-by: Fabrice Fontaine +--- + btt/devmap.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/btt/devmap.c b/btt/devmap.c +index 0553a9e..5fc1cb2 100644 +--- a/btt/devmap.c ++++ b/btt/devmap.c +@@ -23,7 +23,7 @@ + + struct devmap { + struct list_head head; +- char device[32], devno[32]; ++ char device[PATH_MAX], devno[PATH_MAX]; + }; + + LIST_HEAD(all_devmaps); +-- +cgit 1.2-0.3.lf.el7 + diff --git a/package/blktrace/blktrace.mk b/package/blktrace/blktrace.mk index 6d1c8e3b92..4ada2e8e4b 100644 --- a/package/blktrace/blktrace.mk +++ b/package/blktrace/blktrace.mk @@ -10,6 +10,9 @@ BLKTRACE_DEPENDENCIES = libaio BLKTRACE_LICENSE = GPL-2.0+ BLKTRACE_LICENSE_FILES = COPYING +# 0001-btt-make-device-devno-use-PATH_MAX-to-avoid-overflow.patch +BLKTRACE_IGNORE_CVES += CVE-2018-10689 + define BLKTRACE_BUILD_CMDS $(TARGET_MAKE_ENV) $(MAKE1) -C $(@D) $(TARGET_CONFIGURE_OPTS) endef