| Message ID | 20210802235524.3417739-3-f4bug@amsat.org |
|---|---|
| State | New |
| Headers | show |
| Series | hw/sd/sdcard: Fix assertion accessing out-of-range addresses with CMD30 | expand |
On Tue, 3 Aug 2021 at 00:55, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote: > > OSS-Fuzz found sending illegal addresses when querying the write > protection bits triggers the assertion added in commit 84816fb63e5 > ("hw/sd/sdcard: Assert if accessing an illegal group"): > > qemu-fuzz-i386-target-generic-fuzz-sdhci-v3: ../hw/sd/sd.c:824: uint32_t sd_wpbits(SDState *, uint64_t): > Assertion `wpnum < sd->wpgrps_size' failed. > #3 0x7f62a8b22c91 in __assert_fail > #4 0x5569adcec405 in sd_wpbits hw/sd/sd.c:824:9 > #5 0x5569adce5f6d in sd_normal_command hw/sd/sd.c:1389:38 > #6 0x5569adce3870 in sd_do_command hw/sd/sd.c:1737:17 > #7 0x5569adcf1566 in sdbus_do_command hw/sd/core.c:100:16 > #8 0x5569adcfc192 in sdhci_send_command hw/sd/sdhci.c:337:12 > #9 0x5569adcfa3a3 in sdhci_write hw/sd/sdhci.c:1186:9 > #10 0x5569adfb3447 in memory_region_write_accessor softmmu/memory.c:492:5 > > It is legal for the CMD30 to query for out-of-range addresses. > Such invalid addresses are simply ignored in the response (write > protection bits set to 0). > > In commit 84816fb63e5 ("hw/sd/sdcard: Assert if accessing an illegal > group") we misplaced the assertion *before* we test the address is > in range. Move it *after*. > > Include the qtest reproducer provided by Alexander Bulekov: > > $ make check-qtest-i386 > ... > Running test qtest-i386/fuzz-sdcard-test > qemu-system-i386: ../hw/sd/sd.c:824: sd_wpbits: Assertion `wpnum < sd->wpgrps_size' failed. > > Cc: qemu-stable@nongnu.org > Reported-by: OSS-Fuzz (Issue 29225) > Suggested-by: Peter Maydell <peter.maydell@linaro.org> > Fixes: 84816fb63e5 ("hw/sd/sdcard: Assert if accessing an illegal group") > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/495 > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> thanks -- PMM
diff --git a/hw/sd/sd.c b/hw/sd/sd.c index 707dcc12a14..bb5dbff68c0 100644 --- a/hw/sd/sd.c +++ b/hw/sd/sd.c @@ -821,7 +821,6 @@ static uint32_t sd_wpbits(SDState *sd, uint64_t addr) wpnum = sd_addr_to_wpnum(addr); for (i = 0; i < 32; i++, wpnum++, addr += WPGROUP_SIZE) { - assert(wpnum < sd->wpgrps_size); if (addr >= sd->size) { /* * If the addresses of the last groups are outside the valid range, @@ -829,6 +828,7 @@ static uint32_t sd_wpbits(SDState *sd, uint64_t addr) */ continue; } + assert(wpnum < sd->wpgrps_size); if (test_bit(wpnum, sd->wp_groups)) { ret |= (1 << i); } diff --git a/tests/qtest/fuzz-sdcard-test.c b/tests/qtest/fuzz-sdcard-test.c index 96602eac7e5..ae14305344a 100644 --- a/tests/qtest/fuzz-sdcard-test.c +++ b/tests/qtest/fuzz-sdcard-test.c @@ -52,6 +52,41 @@ static void oss_fuzz_29225(void) qtest_quit(s); } +/* + * https://gitlab.com/qemu-project/qemu/-/issues/495 + * Used to trigger: + * Assertion `wpnum < sd->wpgrps_size' failed. + */ +static void oss_fuzz_36217(void) +{ + QTestState *s; + + s = qtest_init(" -display none -m 32 -nodefaults -nographic" + " -device sdhci-pci,sd-spec-version=3 " + "-device sd-card,drive=d0 " + "-drive if=none,index=0,file=null-co://,format=raw,id=d0"); + + qtest_outl(s, 0xcf8, 0x80001010); + qtest_outl(s, 0xcfc, 0xe0000000); + qtest_outl(s, 0xcf8, 0x80001004); + qtest_outw(s, 0xcfc, 0x02); + qtest_bufwrite(s, 0xe000002c, "\x05", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x37", 0x1); + qtest_bufwrite(s, 0xe000000a, "\x01", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x29", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x02", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x03", 0x1); + qtest_bufwrite(s, 0xe0000005, "\x01", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x06", 0x1); + qtest_bufwrite(s, 0xe000000c, "\x05", 0x1); + qtest_bufwrite(s, 0xe000000e, "\x20", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x08", 0x1); + qtest_bufwrite(s, 0xe000000b, "\x3d", 0x1); + qtest_bufwrite(s, 0xe000000f, "\x1e", 0x1); + + qtest_quit(s); +} + int main(int argc, char **argv) { const char *arch = qtest_get_arch(); @@ -60,6 +95,7 @@ int main(int argc, char **argv) if (strcmp(arch, "i386") == 0) { qtest_add_func("fuzz/sdcard/oss_fuzz_29225", oss_fuzz_29225); + qtest_add_func("fuzz/sdcard/oss_fuzz_36217", oss_fuzz_36217); } return g_test_run();
OSS-Fuzz found sending illegal addresses when querying the write protection bits triggers the assertion added in commit 84816fb63e5 ("hw/sd/sdcard: Assert if accessing an illegal group"): qemu-fuzz-i386-target-generic-fuzz-sdhci-v3: ../hw/sd/sd.c:824: uint32_t sd_wpbits(SDState *, uint64_t): Assertion `wpnum < sd->wpgrps_size' failed. #3 0x7f62a8b22c91 in __assert_fail #4 0x5569adcec405 in sd_wpbits hw/sd/sd.c:824:9 #5 0x5569adce5f6d in sd_normal_command hw/sd/sd.c:1389:38 #6 0x5569adce3870 in sd_do_command hw/sd/sd.c:1737:17 #7 0x5569adcf1566 in sdbus_do_command hw/sd/core.c:100:16 #8 0x5569adcfc192 in sdhci_send_command hw/sd/sdhci.c:337:12 #9 0x5569adcfa3a3 in sdhci_write hw/sd/sdhci.c:1186:9 #10 0x5569adfb3447 in memory_region_write_accessor softmmu/memory.c:492:5 It is legal for the CMD30 to query for out-of-range addresses. Such invalid addresses are simply ignored in the response (write protection bits set to 0). In commit 84816fb63e5 ("hw/sd/sdcard: Assert if accessing an illegal group") we misplaced the assertion *before* we test the address is in range. Move it *after*. Include the qtest reproducer provided by Alexander Bulekov: $ make check-qtest-i386 ... Running test qtest-i386/fuzz-sdcard-test qemu-system-i386: ../hw/sd/sd.c:824: sd_wpbits: Assertion `wpnum < sd->wpgrps_size' failed. Cc: qemu-stable@nongnu.org Reported-by: OSS-Fuzz (Issue 29225) Suggested-by: Peter Maydell <peter.maydell@linaro.org> Fixes: 84816fb63e5 ("hw/sd/sdcard: Assert if accessing an illegal group") Resolves: https://gitlab.com/qemu-project/qemu/-/issues/495 Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- hw/sd/sd.c | 2 +- tests/qtest/fuzz-sdcard-test.c | 36 ++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 1 deletion(-)