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>
4ac0b72bae