Commit Graph

2 Commits

Author SHA1 Message Date
Philippe Mathieu-Daudé
4ac0b72bae hw/sd/sdcard: Fix assertion accessing out-of-range addresses with CMD30
OSS-Fuzz found sending illegal addresses when querying the write
protection bits triggers the assertion added in commit 84816fb63e
("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💯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 84816fb63e ("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: 84816fb63e ("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>
Message-Id: <20210802235524.3417739-3-f4bug@amsat.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Alexander Bulekov <alxndr@bu.edu>
2021-08-03 19:34:51 +02:00
Philippe Mathieu-Daudé
59b63d78be hw/sd/sdcard: Check for valid address range in SEND_WRITE_PROT (CMD30)
OSS-Fuzz found sending illegal addresses when querying the write
protection bits triggers an assertion:

  qemu-fuzz-i386: hw/sd/sd.c:824: uint32_t sd_wpbits(SDState *, uint64_t): Assertion `wpnum < sd->wpgrps_size' failed.
  ==11578== ERROR: libFuzzer: deadly signal
  #8 0x7ffff628e091 in __assert_fail
  #9 0x5555588f1a3c in sd_wpbits hw/sd/sd.c:824:9
  #10 0x5555588dd271 in sd_normal_command hw/sd/sd.c:1383:38
  #11 0x5555588d777c in sd_do_command hw/sd/sd.c
  #12 0x555558cb25a0 in sdbus_do_command hw/sd/core.c💯16
  #13 0x555558e02a9a in sdhci_send_command hw/sd/sdhci.c:337:12
  #14 0x555558dffa46 in sdhci_write hw/sd/sdhci.c:1187:9
  #15 0x5555598b9d76 in memory_region_write_accessor softmmu/memory.c:489:5

Similarly to commit 8573378e62 ("hw/sd: fix out-of-bounds check
for multi block reads"), check the address range before sending
the status of the write protection bits.

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.

Reported-by: OSS-Fuzz (Issue 29225)
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/450
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20210702155900.148665-4-f4bug@amsat.org>
2021-07-12 12:27:38 +02:00