| Message ID | 20230926131128.3771508-1-giulio.benetti@benettiengineering.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] mmc-utils: fix potential overflow | expand |
diff --git a/mmc_cmds.c b/mmc_cmds.c index 10d063d..ae7b876 100644 --- a/mmc_cmds.c +++ b/mmc_cmds.c @@ -2065,7 +2065,7 @@ int do_sanitize(int nargs, char **argv) } \ else if (r > 0) \ ret += r; \ - } while (r != 0 && (size_t)ret != nbyte); \ + } while (r != 0 && (size_t)ret < nbyte); \ \ ret; \ })
Building with _FORTIFY_SOURCE=3 results in: from mmc_cmds.c:20: In function ‘read’, inlined from ‘do_rpmb_write_key’ at mmc_cmds.c:2233:8: /home/giuliobenetti/br_reproduce/a53922c5db3e605a5e81e53c034f45017ebb7db7/output/host/mipsel-buildroot-linux-gnu/sysroot/usr/include/bits/unistd.h:38:10: error: ‘__read_alias’ writing 228 or more bytes into a region of size 32 overflows the destination [-Werror=stringop-overflow=] 38 | return __glibc_fortify (read, __nbytes, sizeof (char), | ^~~~~~~~~~~~~~~ mmc_cmds.c: In function ‘do_rpmb_write_key’: mmc_cmds.c:2087:19: note: destination object ‘key_mac’ of size 32 2087 | u_int8_t key_mac[32]; | ^~~~~~~ /home/giuliobenetti/br_reproduce/a53922c5db3e605a5e81e53c034f45017ebb7db7/output/host/mipsel-buildroot-linux-gnu/sysroot/usr/include/bits/unistd.h:26:16: note: in a call to function ‘__read_alias’ declared with attribute ‘access (write_only, 2, 3)’ 26 | extern ssize_t __REDIRECT (__read_alias, (int __fd, void *__buf, | ^~~~~~~~~~ To work around this let's check if the return of read() is lower than the nbyte requested instead of not equal. Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> --- V1->V2: * corrected commit log --- mmc_cmds.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)