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linux-user: Use elf_et_dyn_base for ET_DYN with interpreter

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Follow the lead of the linux kernel in fs/binfmt_elf.c,
in which an ET_DYN executable which uses an interpreter
(usually a PIE executable) is loaded away from where the
interpreter itself will be loaded.

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Helge Deller <deller@gmx.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-08-02 15:58:07 -07:00
parent ad25051bae
commit 1ea06ded0d
1 changed files with 25 additions and 2 deletions
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27
linux-user/elfload.c
View file

@ -3107,6 +3107,8 @@ static void load_elf_image(const char *image_name, int image_fd,
} }
} }
load_addr = loaddr;
if (pinterp_name != NULL) { if (pinterp_name != NULL) {
/* /*
* This is the main executable. * This is the main executable.
@ -3136,11 +3138,32 @@ static void load_elf_image(const char *image_name, int image_fd,
*/ */
probe_guest_base(image_name, loaddr, hiaddr); probe_guest_base(image_name, loaddr, hiaddr);
} else { } else {
abi_ulong align;
/* /*
* The binary is dynamic, but we still need to * The binary is dynamic, but we still need to
* select guest_base. In this case we pass a size. * select guest_base. In this case we pass a size.
*/ */
probe_guest_base(image_name, 0, hiaddr - loaddr); probe_guest_base(image_name, 0, hiaddr - loaddr);
/*
* Avoid collision with the loader by providing a different
* default load address.
*/
load_addr += elf_et_dyn_base;
/*
* TODO: Better support for mmap alignment is desirable.
* Since we do not have complete control over the guest
* address space, we prefer the kernel to choose some address
* rather than force the use of LOAD_ADDR via MAP_FIXED.
* But without MAP_FIXED we cannot guarantee alignment,
* only suggest it.
*/
align = pow2ceil(info->alignment);
if (align) {
load_addr &= -align;
}
} }
} }
@ -3155,13 +3178,13 @@ static void load_elf_image(const char *image_name, int image_fd,
* *
* Otherwise this is ET_DYN, and we are searching for a location * Otherwise this is ET_DYN, and we are searching for a location
* that can hold the memory space required. If the image is * that can hold the memory space required. If the image is
* pre-linked, LOADDR will be non-zero, and the kernel should * pre-linked, LOAD_ADDR will be non-zero, and the kernel should
* honor that address if it happens to be free. * honor that address if it happens to be free.
* *
* In both cases, we will overwrite pages in this range with mappings * In both cases, we will overwrite pages in this range with mappings
* from the executable. * from the executable.
*/ */
load_addr = target_mmap(loaddr, (size_t)hiaddr - loaddr + 1, PROT_NONE, load_addr = target_mmap(load_addr, (size_t)hiaddr - loaddr + 1, PROT_NONE,
MAP_PRIVATE | MAP_ANON | MAP_NORESERVE | MAP_PRIVATE | MAP_ANON | MAP_NORESERVE |
(ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE : 0), (ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE : 0),
-1, 0); -1, 0);