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Alec Brown
27a14a8ae2
In bsdXX.c and multiboot_elfxx.c, e_shnum is used to obtain the number of section header table entries, but it wasn't being checked if the value was there. According to the elf(5) manual page, "If the number of entries in the section header table is larger than or equal to SHN_LORESERVE (0xff00), e_shnum holds the value zero and the real number of entries in the section header table is held in the sh_size member of the initial entry in section header table. Otherwise, the sh_size member of the initial entry in the section header table holds the value zero." Since this check wasn't being made, grub_elfXX_get_shnum() is being added to elfXX.c to make this check and use whichever member doesn't have a value of zero. If both are zero, then we must return an error. We also need to make sure that e_shnum doesn't have a value greater than or equal to SHN_LORESERVE and sh_size isn't less than SHN_LORESERVE. In order to get this function to work, the type ElfXX_Shnum is being added where Elf32_Shnum defines Elf32_Word and Elf64_Shnum defines Elf64_Xword. This new type is needed because if shnum obtains a value from sh_size, sh_size could be of type El32_Word for Elf32_Shdr structures or Elf64_Xword for Elf64_Shdr structures. Note that even though elf.c and elfXX.c are located in grub-core/kern, they are compiled as modules and don't need the EXPORT_FUNC() macro to define the functions in elf.h. For a few smaller changes, changed casts of shnum to match variables being set as well as dropped casts when unnecessary and fixed spacing errors in bsdXX.c. Also, shnum is an unsigned integer and is compared to int i in multiboot_elfxx.c, it should be unsigned to match shnum. Signed-off-by: Alec Brown <alec.r.brown@oracle.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>