Le 29/05/2018 à 09:47, Geert Uytterhoeven a écrit :
Hi Christophe, CC Geoff On Tue, May 29, 2018 at 8:03 AM, Christophe Leroy <christophe.le...@c-s.fr> wrote:CC arch/powerpc/kernel/nvram_64.o arch/powerpc/kernel/nvram_64.c: In function 'nvram_create_partition': arch/powerpc/kernel/nvram_64.c:1042:2: error: 'strncpy' specified bound 12 equals destination size [-Werror=stringop-truncation] strncpy(new_part->header.name, name, 12); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CC arch/powerpc/kernel/trace/ftrace.o In function 'make_field', inlined from 'ps3_repository_read_boot_dat_address' at arch/powerpc/platforms/ps3/repository.c:900:9: arch/powerpc/platforms/ps3/repository.c:106:2: error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation] strncpy((char *)&n, text, 8); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>Thanks for your patch!--- a/arch/powerpc/kernel/nvram_64.c +++ b/arch/powerpc/kernel/nvram_64.c @@ -1039,7 +1039,7 @@ loff_t __init nvram_create_partition(const char *name, int sig, new_part->index = free_part->index; new_part->header.signature = sig; new_part->header.length = size; - strncpy(new_part->header.name, name, 12); + memcpy(new_part->header.name, name, strnlen(name, sizeof(new_part->header.name)));The comment for nvram_header.lgnth says: /* Terminating null required only for names < 12 chars. */ This will not terminate the string with a zero (the struct is allocated with kmalloc). So the original code is correct, the new one isn't.
Right, then I have to first zeroize the destination.
new_part->header.checksum = nvram_checksum(&new_part->header); rc = nvram_write_header(new_part); diff --git a/arch/powerpc/platforms/ps3/repository.c b/arch/powerpc/platforms/ps3/repository.c index 50dbaf24b1ee..e49c887787c4 100644 --- a/arch/powerpc/platforms/ps3/repository.c +++ b/arch/powerpc/platforms/ps3/repository.c @@ -101,9 +101,9 @@ static u64 make_first_field(const char *text, u64 index) static u64 make_field(const char *text, u64 index) { - u64 n; + u64 n = 0; - strncpy((char *)&n, text, 8); + memcpy((char *)&n, text, strnlen(text, sizeof(n)));This changes behavior: strncpy() fills the remainder of the buffer with zeroes. I don't remember the details of the PS3 repository structure, but given this writes to a fixed size u64 buffer, I'd expect the PS3 hypervisor code to (1) rely on the zero padding, and (2) not need a zero terminator if there are 8 characters in the buffer, so probably the original code is correct, and the "fixed" code isn't.
Here I have set n to 0 prior to the copy, so the buffer IS zero padded. Christophe
Has this been tested on a PS3?return n + index; }Gr{oetje,eeting}s, Geert
