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author | Richard Henderson <richard.henderson@linaro.org> | 2023-08-02 15:58:07 -0700 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2023-08-08 13:27:17 -0700 |
commit | 1ea06ded0de5adcd40a0122ea73c9761f488bfba (patch) | |
tree | e21366bd68ef8fe9fd45ae03b177462890312077 | |
parent | ad25051bae392ce35437cdf996aedecc0772af2f (diff) | |
download | qemu-1ea06ded0de5adcd40a0122ea73c9761f488bfba.zip qemu-1ea06ded0de5adcd40a0122ea73c9761f488bfba.tar.gz qemu-1ea06ded0de5adcd40a0122ea73c9761f488bfba.tar.bz2 |
linux-user: Use elf_et_dyn_base for ET_DYN with interpreter
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>
-rw-r--r-- | linux-user/elfload.c | 27 |
1 files changed, 25 insertions, 2 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 1b4bb2d..d1b278d 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3107,6 +3107,8 @@ static void load_elf_image(const char *image_name, int image_fd, } } + load_addr = loaddr; + if (pinterp_name != NULL) { /* * 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); } else { + abi_ulong align; + /* * The binary is dynamic, but we still need to * select guest_base. In this case we pass a size. */ 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 * 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. * * In both cases, we will overwrite pages in this range with mappings * 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 | (ehdr->e_type == ET_EXEC ? MAP_FIXED_NOREPLACE : 0), -1, 0); |