From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Darren Kenny Date: Fri, 4 Dec 2020 15:04:28 +0000 Subject: [PATCH] util/glue-efi: Fix incorrect use of a possibly negative value It is possible for the ftell() function to return a negative value, although it is fairly unlikely here, we should be checking for a negative value before we assign it to an unsigned value. Fixes: CID 73744 Signed-off-by: Darren Kenny Reviewed-by: Daniel Kiper --- util/glue-efi.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/util/glue-efi.c b/util/glue-efi.c index 68f53168b..de0fa6d33 100644 --- a/util/glue-efi.c +++ b/util/glue-efi.c @@ -39,13 +39,23 @@ write_fat (FILE *in32, FILE *in64, FILE *out, const char *out_filename, struct grub_macho_fat_header head; struct grub_macho_fat_arch arch32, arch64; grub_uint32_t size32, size64; + long size; char *buf; fseek (in32, 0, SEEK_END); - size32 = ftell (in32); + size = ftell (in32); + if (size < 0) + grub_util_error ("cannot get end of input file '%s': %s", + name32, strerror (errno)); + size32 = (grub_uint32_t) size; fseek (in32, 0, SEEK_SET); + fseek (in64, 0, SEEK_END); - size64 = ftell (in64); + size = ftell (in64); + if (size < 0) + grub_util_error ("cannot get end of input file '%s': %s", + name64, strerror (errno)); + size64 = (grub_uint64_t) size; fseek (in64, 0, SEEK_SET); head.magic = grub_cpu_to_le32_compile_time (GRUB_MACHO_FAT_EFI_MAGIC);