diff options
Diffstat (limited to 'kexec/kexec-uImage.c')
| -rw-r--r-- | kexec/kexec-uImage.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/kexec/kexec-uImage.c b/kexec/kexec-uImage.c new file mode 100644 index 0000000..016be10 --- /dev/null +++ b/kexec/kexec-uImage.c @@ -0,0 +1,283 @@ +#define _GNU_SOURCE +#include <stdlib.h> +#include <stdint.h> +#include <string.h> +#include <sys/types.h> +#include <image.h> +#include <getopt.h> +#include <arch/options.h> +#include "kexec.h" +#include <kexec-uImage.h> + +#ifdef HAVE_LIBZ +#include <zlib.h> +#endif +/* + * Basic uImage loader. Not rocket science. + */ + +/* + * Returns the image type if everything goes well. This would + * allow the user to decide if the image is of their interest. + * + * Returns -1 on a corrupted image + * + * Returns 0 if this is not a uImage + */ +int uImage_probe(const char *buf, off_t len, unsigned int arch) +{ + struct image_header header; +#ifdef HAVE_LIBZ + unsigned int crc; + unsigned int hcrc; +#endif + + if ((uintmax_t)len < (uintmax_t)sizeof(header)) + return -1; + + memcpy(&header, buf, sizeof(header)); + if (be32_to_cpu(header.ih_magic) != IH_MAGIC) + return 0; +#ifdef HAVE_LIBZ + hcrc = be32_to_cpu(header.ih_hcrc); + header.ih_hcrc = 0; + crc = crc32(0, (void *)&header, sizeof(header)); + if (crc != hcrc) { + printf("Header checksum of the uImage does not match\n"); + return -1; + } +#endif + switch (header.ih_type) { + case IH_TYPE_KERNEL: + case IH_TYPE_KERNEL_NOLOAD: + break; + case IH_TYPE_RAMDISK: + break; + default: + printf("uImage type %d unsupported\n", header.ih_type); + return -1; + } + + if (header.ih_os != IH_OS_LINUX) { + printf("uImage os %d unsupported\n", header.ih_os); + return -1; + } + + if (header.ih_arch != arch) { + printf("uImage arch %d unsupported\n", header.ih_arch); + return -1; + } + + switch (header.ih_comp) { + case IH_COMP_NONE: +#ifdef HAVE_LIBZ + case IH_COMP_GZIP: +#endif + break; + default: + printf("uImage uses unsupported compression method\n"); + return -1; + } + + if (be32_to_cpu(header.ih_size) > len - sizeof(header)) { + printf("uImage header claims that image has %d bytes\n", + be32_to_cpu(header.ih_size)); + printf("we read only %lld bytes.\n", + (long long)len - sizeof(header)); + return -1; + } +#ifdef HAVE_LIBZ + crc = crc32(0, (void *)buf + sizeof(header), be32_to_cpu(header.ih_size)); + if (crc != be32_to_cpu(header.ih_dcrc)) { + printf("uImage: The data CRC does not match. Computed: %08x " + "expected %08x\n", crc, + be32_to_cpu(header.ih_dcrc)); + return -1; + } +#endif + return (int)header.ih_type; +} + +/* + * To conform to the 'probe' routine in file_type struct, + * we return : + * 0 - If the image is valid 'type' image. + * + * Now, we have to pass on the 'errors' in the image. So, + * + * -1 - If the image is corrupted. + * 1 - If the image is not a uImage. + */ + +int uImage_probe_kernel(const char *buf, off_t len, unsigned int arch) +{ + int type = uImage_probe(buf, len, arch); + if (type < 0) + return -1; + + return !(type == IH_TYPE_KERNEL || type == IH_TYPE_KERNEL_NOLOAD); +} + +int uImage_probe_ramdisk(const char *buf, off_t len, unsigned int arch) +{ + int type = uImage_probe(buf, len, arch); + + if (type < 0) + return -1; + return !(type == IH_TYPE_RAMDISK); +} + +#ifdef HAVE_LIBZ +/* gzip flag byte */ +#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ +#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ +#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ +#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ +#define COMMENT 0x10 /* bit 4 set: file comment present */ +#define RESERVED 0xE0 /* bits 5..7: reserved */ + +static int uImage_gz_load(const char *buf, off_t len, + struct Image_info *image) +{ + int ret; + z_stream strm; + unsigned int skip; + unsigned int flags; + unsigned char *uncomp_buf; + unsigned int mem_alloc; + + mem_alloc = 10 * 1024 * 1024; + uncomp_buf = malloc(mem_alloc); + if (!uncomp_buf) + return -1; + + memset(&strm, 0, sizeof(strm)); + + /* Skip magic, method, time, flags, os code ... */ + skip = 10; + + /* check GZ magic */ + if (buf[0] != 0x1f || buf[1] != 0x8b) { + free(uncomp_buf); + return -1; + } + + flags = buf[3]; + if (buf[2] != Z_DEFLATED || (flags & RESERVED) != 0) { + puts ("Error: Bad gzipped data\n"); + free(uncomp_buf); + return -1; + } + + if (flags & EXTRA_FIELD) { + skip += 2; + skip += buf[10]; + skip += buf[11] << 8; + } + if (flags & ORIG_NAME) { + while (buf[skip++]) + ; + } + if (flags & COMMENT) { + while (buf[skip++]) + ; + } + if (flags & HEAD_CRC) + skip += 2; + + strm.avail_in = len - skip; + strm.next_in = (void *)buf + skip; + + /* - activates parsing gz headers */ + ret = inflateInit2(&strm, -MAX_WBITS); + if (ret != Z_OK) { + free(uncomp_buf); + return -1; + } + + strm.next_out = uncomp_buf; + strm.avail_out = mem_alloc; + + do { + ret = inflate(&strm, Z_FINISH); + if (ret == Z_STREAM_END) + break; + + if (ret == Z_OK || ret == Z_BUF_ERROR) { + void *new_buf; + int inc_buf = 5 * 1024 * 1024; + + mem_alloc += inc_buf; + new_buf = realloc(uncomp_buf, mem_alloc); + if (!new_buf) { + inflateEnd(&strm); + free(uncomp_buf); + return -1; + } + + uncomp_buf = new_buf; + strm.next_out = uncomp_buf + mem_alloc - inc_buf; + strm.avail_out = inc_buf; + } else { + free(uncomp_buf); + printf("Error during decompression %d\n", ret); + return -1; + } + } while (1); + + inflateEnd(&strm); + image->buf = (char *)uncomp_buf; + image->len = mem_alloc - strm.avail_out; + return 0; +} +#else +static int uImage_gz_load(const char *UNUSED(buf), off_t UNUSED(len), + struct Image_info *UNUSED(image)) +{ + return -1; +} +#endif + +int uImage_load(const char *buf, off_t len, struct Image_info *image) +{ + const struct image_header *header = (const struct image_header *)buf; + const char *img_buf = buf + sizeof(struct image_header); + off_t img_len = be32_to_cpu(header->ih_size); + + /* + * Prevent loading a modified image. + * CRC check is perfomed only when zlib is compiled + * in. This check will help us to detect + * size related vulnerabilities. + */ + if (img_len != (len - sizeof(struct image_header))) { + printf("Image size doesn't match the header\n"); + return -1; + } + + image->base = cpu_to_be32(header->ih_load); + image->ep = cpu_to_be32(header->ih_ep); + switch (header->ih_comp) { + case IH_COMP_NONE: + image->buf = img_buf; + image->len = img_len; + return 0; + break; + + case IH_COMP_GZIP: + /* + * uboot doesn't decompress the RAMDISK images. + * Comply to the uboot behaviour. + */ + if (header->ih_type == IH_TYPE_RAMDISK) { + image->buf = img_buf; + image->len = img_len; + return 0; + } else + return uImage_gz_load(img_buf, img_len, image); + break; + + default: + return -1; + } +} |