diff options
| -rw-r--r-- | futility/dump_kernel_config_lib.c | 141 |
1 files changed, 79 insertions, 62 deletions
diff --git a/futility/dump_kernel_config_lib.c b/futility/dump_kernel_config_lib.c index 93a51581..1baa2d58 100644 --- a/futility/dump_kernel_config_lib.c +++ b/futility/dump_kernel_config_lib.c @@ -8,115 +8,132 @@ #include <stdio.h> #include <string.h> #include <sys/mman.h> +#include <sys/fcntl.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> #include "host_common.h" #include "kernel_blob.h" #include "vboot_api.h" #include "vboot_host.h" -static uint8_t *GetKernelConfig(uint8_t *blob, size_t blob_size, - uint64_t kernel_body_load_address) +typedef ssize_t (*ReadFullyFn)(void *ctx, void *buf, size_t count); + +static ssize_t ReadFullyWithRead(void *ctx, void *buf, size_t count) { + ssize_t nr_read = 0; + int fd = *((int*)ctx); + while (nr_read < count) { + ssize_t to_read = count - nr_read; + ssize_t chunk = read(fd, buf + nr_read, to_read); + if (chunk < 0) { + return -1; + } else if (chunk == 0) { + break; + } + nr_read += chunk; + } + return nr_read; +} + +/* Skip the stream by calling |read_fn| many times. Return 0 on success. */ +static int SkipWithRead(void *ctx, ReadFullyFn read_fn, size_t count) +{ + char buf[1024]; + ssize_t nr_skipped = 0; + while (nr_skipped < count) { + ssize_t to_read = count - nr_skipped; + if (to_read > sizeof(buf)) { + to_read = sizeof(buf); + } + if (read_fn(ctx, buf, to_read) != to_read) { + return -1; + } + nr_skipped += to_read; + } + return 0; +} - VbKeyBlockHeader *key_block; - VbKernelPreambleHeader *preamble; +static char *FindKernelConfigFromStream(void *ctx, ReadFullyFn read_fn, + uint64_t kernel_body_load_address) +{ + VbKeyBlockHeader key_block; + VbKernelPreambleHeader preamble; uint32_t now = 0; uint32_t offset = 0; /* Skip the key block */ - key_block = (VbKeyBlockHeader *) blob; - now += key_block->key_block_size; - if (now + blob > blob + blob_size) { + if (read_fn(ctx, &key_block, sizeof(key_block)) != sizeof(key_block)) { + VbExError("not enough data to fill key block header\n"); + return NULL; + } + ssize_t to_skip = key_block.key_block_size - sizeof(key_block); + if (to_skip < 0 || SkipWithRead(ctx, read_fn, to_skip)) { VbExError("key_block_size advances past the end of the blob\n"); return NULL; } + now += key_block.key_block_size; /* Open up the preamble */ - preamble = (VbKernelPreambleHeader *) (blob + now); - now += preamble->preamble_size; - if (now + blob > blob + blob_size) { + if (read_fn(ctx, &preamble, sizeof(preamble)) != sizeof(preamble)) { + VbExError("not enough data to fill preamble\n"); + return NULL; + } + to_skip = preamble.preamble_size - sizeof(preamble); + if (to_skip < 0 || SkipWithRead(ctx, read_fn, to_skip)) { VbExError("preamble_size advances past the end of the blob\n"); return NULL; } + now += preamble.preamble_size; /* Read body_load_address from preamble if no * kernel_body_load_address */ if (kernel_body_load_address == USE_PREAMBLE_LOAD_ADDR) - kernel_body_load_address = preamble->body_load_address; + kernel_body_load_address = preamble.body_load_address; /* The x86 kernels have a pointer to the kernel commandline in the * zeropage table, but that's irrelevant for ARM. Both types keep the * config blob in the same place, so just go find it. */ - offset = preamble->bootloader_address - + offset = preamble.bootloader_address - (kernel_body_load_address + CROS_PARAMS_SIZE + CROS_CONFIG_SIZE) + now; - if (offset > blob_size) { + to_skip = offset - now; + if (to_skip < 0 || SkipWithRead(ctx, read_fn, to_skip)) { VbExError("params are outside of the memory blob: %x\n", offset); return NULL; } - return blob + offset; -} - -static void *MMapFile(const char *filename, size_t *size) -{ - FILE *f; - uint8_t *buf; - long file_size = 0; - - f = fopen(filename, "rb"); - if (!f) { - VBDEBUG(("Unable to open file %s\n", filename)); - return NULL; - } - - fseek(f, 0, SEEK_END); - file_size = ftell(f); - rewind(f); - - if (file_size <= 0) { - fclose(f); + char *ret = malloc(CROS_CONFIG_SIZE); + if (!ret) { + VbExError("No memory\n"); return NULL; } - *size = (size_t) file_size; - - /* Uses a host primitive as this is not meant for firmware use. */ - buf = mmap(NULL, *size, PROT_READ, MAP_PRIVATE, fileno(f), 0); - if (buf == MAP_FAILED) { - VbExError("Failed to mmap the file %s\n", filename); - fclose(f); - return NULL; + if (read_fn(ctx, ret, CROS_CONFIG_SIZE) != CROS_CONFIG_SIZE) { + VbExError("Cannot read kernel config\n"); + free(ret); + ret = NULL; } - - fclose(f); - return buf; + return ret; } char *FindKernelConfig(const char *infile, uint64_t kernel_body_load_address) { - uint8_t *blob; - size_t blob_size; - uint8_t *config = NULL; char *newstr = NULL; - blob = MMapFile(infile, &blob_size); - if (!blob) { - VbExError("Error reading input file\n"); - return 0; + int fd = open(infile, O_RDONLY | O_CLOEXEC | O_LARGEFILE); + if (fd < 0) { + VbExError("Cannot open %s\n", infile); + return NULL; } - config = GetKernelConfig(blob, blob_size, kernel_body_load_address); - if (!config) { - VbExError("Error parsing input file\n"); - munmap(blob, blob_size); - return 0; - } + void *ctx = &fd; + ReadFullyFn read_fn = ReadFullyWithRead; - newstr = strndup((char *)config, CROS_CONFIG_SIZE); - if (!newstr) - VbExError("Can't allocate new string\n"); + newstr = FindKernelConfigFromStream(ctx, read_fn, + kernel_body_load_address); - munmap(blob, blob_size); + close(fd); return newstr; } |