Hi Sven,
On Mon, 22 Nov 2021 08:13:59 +0100
Sven Schnelle <svens@xxxxxxxxxxxxx> wrote:
> Newer s390 kernels support a command line size longer than 896
> bytes. Such kernels contain a new member in the parameter area,
> which might be utilized by tools like kexec. Older kernels have
> the location initialized to zero, so we check whether there's a
> non-zero number present and use that. If there isn't, we fallback
> to the legacy command line size of 896 bytes.
>
> Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
> Reviewed-by: Alexander Egorenkov <egorenar@xxxxxxxxxxxxx>
> ---
> kexec/arch/s390/kexec-image.c | 53 ++++++++++++++++++++++++-----------
> kexec/arch/s390/kexec-s390.h | 19 +++++++------
> 2 files changed, 46 insertions(+), 26 deletions(-)
>
> diff --git a/kexec/arch/s390/kexec-image.c b/kexec/arch/s390/kexec-image.c
> index 3c24fdfe3c7c..7747d02399db 100644
> --- a/kexec/arch/s390/kexec-image.c
> +++ b/kexec/arch/s390/kexec-image.c
> @@ -25,7 +25,7 @@
> #include <fcntl.h>
>
> static uint64_t crash_base, crash_end;
> -static char command_line[COMMAND_LINESIZE];
> +static char *command_line;
isn't this the perfect opportunity to get rid of this global variable
and...
> static void add_segment_check(struct kexec_info *info, const void *buf,
> size_t bufsz, unsigned long base, size_t memsz)
> @@ -38,11 +38,16 @@ static void add_segment_check(struct kexec_info *info, const void *buf,
>
> int command_line_add(const char *str)
... simply pass the pointer as an argument ;)
Thanks
Philipp
> {
> - if (strlen(command_line) + strlen(str) + 1 > COMMAND_LINESIZE) {
> - fprintf(stderr, "Command line too long.\n");
> + char *tmp = NULL;
> +
> + tmp = concat_cmdline(command_line, str);
> + if (!tmp) {
> + fprintf(stderr, "out of memory\n");
> return -1;
> }
> - strcat(command_line, str);
> +
> + free(command_line);
> + command_line = tmp;
> return 0;
> }
>
> @@ -78,6 +83,8 @@ int image_s390_load_file(int argc, char **argv, struct kexec_info *info)
> if (info->initrd_fd == -1) {
> fprintf(stderr, "Could not open initrd file %s:%s\n",
> ramdisk, strerror(errno));
> + free(command_line);
> + command_line = NULL;
> return -1;
> }
> }
> @@ -97,7 +104,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> const char *ramdisk;
> off_t ramdisk_len;
> unsigned int ramdisk_origin;
> - int opt;
> + int opt, ret = -1;
>
> if (info->file_mode)
> return image_s390_load_file(argc, argv, info);
> @@ -112,7 +119,6 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> };
> static const char short_options[] = KEXEC_OPT_STR "";
>
> - command_line[0] = 0;
> ramdisk = NULL;
> ramdisk_len = 0;
> ramdisk_origin = 0;
> @@ -132,7 +138,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> if (info->kexec_flags & KEXEC_ON_CRASH) {
> if (parse_iomem_single("Crash kernel\n", &crash_base,
> &crash_end))
> - return -1;
> + goto out;
> }
>
> /* Add kernel segment */
> @@ -151,7 +157,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> rd_buffer = slurp_file_mmap(ramdisk, &ramdisk_len);
> if (rd_buffer == NULL) {
> fprintf(stderr, "Could not read ramdisk.\n");
> - return -1;
> + goto out;
> }
> ramdisk_origin = MAX(RAMDISK_ORIGIN_ADDR, kernel_size);
> ramdisk_origin = _ALIGN_UP(ramdisk_origin, 0x100000);
> @@ -160,7 +166,7 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> }
> if (info->kexec_flags & KEXEC_ON_CRASH) {
> if (load_crashdump_segments(info, crash_base, crash_end))
> - return -1;
> + goto out;
> } else {
> info->entry = (void *) IMAGE_READ_OFFSET;
> }
> @@ -183,15 +189,28 @@ image_s390_load(int argc, char **argv, const char *kernel_buf,
> *tmp = crash_end - crash_base + 1;
> }
> }
> - /*
> - * We will write a probably given command line.
> - * First, erase the old area, then setup the new parameters:
> - */
> - if (strlen(command_line) != 0) {
> - memset(krnl_buffer + COMMAND_LINE_OFFS, 0, COMMAND_LINESIZE);
> - memcpy(krnl_buffer + COMMAND_LINE_OFFS, command_line, strlen(command_line));
> +
> + if (command_line) {
> + unsigned long maxsize;
> + char *dest = krnl_buffer + COMMAND_LINE_OFFS;
> +
> + maxsize = *(unsigned long *)(krnl_buffer + MAX_COMMAND_LINESIZE_OFFS);
> + if (!maxsize)
> + maxsize = LEGACY_COMMAND_LINESIZE;
> +
> + if (strlen(command_line) > maxsize-1) {
> + fprintf(stderr, "command line too long, maximum allowed size %ld\n",
> + maxsize-1);
> + goto out;
> + }
> + strncpy(dest, command_line, maxsize-1);
> + dest[maxsize-1] = '\0';
> }
> - return 0;
> + ret = 0;
> +out:
> + free(command_line);
> + command_line = NULL;
> + return ret;
> }
>
> int
> diff --git a/kexec/arch/s390/kexec-s390.h b/kexec/arch/s390/kexec-s390.h
> index ef53b111e167..1b0e04848460 100644
> --- a/kexec/arch/s390/kexec-s390.h
> +++ b/kexec/arch/s390/kexec-s390.h
> @@ -10,16 +10,17 @@
> #ifndef KEXEC_S390_H
> #define KEXEC_S390_H
>
> -#define IMAGE_READ_OFFSET 0x10000
> +#define IMAGE_READ_OFFSET 0x10000
>
> -#define RAMDISK_ORIGIN_ADDR 0x800000
> -#define INITRD_START_OFFS 0x408
> -#define INITRD_SIZE_OFFS 0x410
> -#define OLDMEM_BASE_OFFS 0x418
> -#define OLDMEM_SIZE_OFFS 0x420
> -#define COMMAND_LINE_OFFS 0x480
> -#define COMMAND_LINESIZE 896
> -#define MAX_MEMORY_RANGES 1024
> +#define RAMDISK_ORIGIN_ADDR 0x800000
> +#define INITRD_START_OFFS 0x408
> +#define INITRD_SIZE_OFFS 0x410
> +#define OLDMEM_BASE_OFFS 0x418
> +#define OLDMEM_SIZE_OFFS 0x420
> +#define MAX_COMMAND_LINESIZE_OFFS 0x430
> +#define COMMAND_LINE_OFFS 0x480
> +#define LEGACY_COMMAND_LINESIZE 896
> +#define MAX_MEMORY_RANGES 1024
>
> #define MAX(x, y) ((x) > (y) ? (x) : (y))
> #define MIN(x, y) ((x) < (y) ? (x) : (y))
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