On Wed, Apr 22, 2020 at 01:21:17PM +0200, Clement Leger wrote:
> When loading an elf file from a mtd device, this allows to parse the
> header and load only the needed data according to the elf size. Without
> that support, loading a elf file from a /dev/mtd would try to read the
> entire partition.
>
> Signed-off-by: Clement Leger <cleger@xxxxxxxxx>
> ---
> common/elf.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++
> include/elf.h | 7 +++++
> 2 files changed, 94 insertions(+)
>
> diff --git a/common/elf.c b/common/elf.c
> index 5534632b2..8b36c2073 100644
> --- a/common/elf.c
> +++ b/common/elf.c
> @@ -5,7 +5,12 @@
>
> #include <common.h>
> #include <elf.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <libfile.h>
> #include <memory.h>
> +#include <unistd.h>
> +#include <linux/fs.h>
>
> struct elf_section {
> struct list_head list;
> @@ -158,3 +163,85 @@ void elf_release_image(struct elf_image *elf)
>
> free(elf);
> }
> +
> +static u64 elf_get_size(struct elf_image *elf)
> +{
> + u64 sh_size = elf_hdr_e_shentsize(elf, elf->buf) *
> + elf_hdr_e_shnum(elf, elf->buf);
> +
> + /*
> + * The section header table is located at the end of the elf file thus
> + * we can take the offset and add the size of this table to obtain the
> + * file size.
> + */
> + return elf_hdr_e_shoff(elf, elf->buf) + sh_size;
> +}
> +
> +struct elf_image *elf_open(const char *filename)
> +{
> + int fd, ret;
> + u64 size;
> + struct elf64_hdr hdr;
> + struct elf_image *elf;
> + ssize_t read_ret;
> +
> + fd = open(filename, O_RDONLY);
> + if (fd < 0) {
> + printf("could not open: %s\n", errno_str());
> + return ERR_PTR(-errno);
> + }
> +
> + if (read(fd, &hdr, sizeof(hdr)) < 0) {
> + printf("could not read elf header: %s\n", errno_str());
> + ret = -errno;
> + goto err_close_fd;
> + }
> +
> + elf = xzalloc(sizeof(*elf));
> +
> + ret = elf_check_init(elf, &hdr);
> + if (ret) {
> + ret = -errno;
> + goto err_free_elf;
> + }
> +
> + size = elf_get_size(elf);
> +
> + elf->buf = xzalloc(size);
You are allocating a potentially unbounded amount of memory. Please use
malloc rather than xzalloc here.
> +
> + lseek(fd, 0, SEEK_SET);
> +
> + read_ret = read(fd, elf->buf, size);
> + if (read_ret < 0) {
> + printf("could not read elf file: %s\n", errno_str());
> + ret = -errno;
> + goto err_free_buf;
> + } else if (read_ret != size) {
> + printf("could not read entire elf file\n");
> + ret = -EIO;
> + goto err_free_buf;
> + }
read_full handles this case.
Sascha
--
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