diff options
Diffstat (limited to 'main/linux-virt-grsec/fix-memory-map-for-PIE-applications.patch')
| -rw-r--r-- | main/linux-virt-grsec/fix-memory-map-for-PIE-applications.patch | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/main/linux-virt-grsec/fix-memory-map-for-PIE-applications.patch b/main/linux-virt-grsec/fix-memory-map-for-PIE-applications.patch new file mode 100644 index 0000000000..e38716f77b --- /dev/null +++ b/main/linux-virt-grsec/fix-memory-map-for-PIE-applications.patch @@ -0,0 +1,68 @@ +From 21f973f87f480e3d24f1cb6c22b71253d25a3ea1 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Timo=20Ter=C3=A4s?= <timo.teras@iki.fi> +Date: Tue, 1 Oct 2013 13:46:04 +0300 +Subject: [PATCH 3.10-grsec] fs/binfmt_elf: fix memory map for PIE applications +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +arch/*/include/asm/elf.h comments say: + ELF_ET_DYN_BASE is the location that an ET_DYN program is loaded + if exec'ed. Typical use of this is to invoke "./ld.so someprog" + to test out a new version of the loader. We need to make sure + that it is out of the way of the program that it will "exec", + and that there is sufficient room for the brk. + +In case we have main application linked as PIE, this can cause +problems as the main program itself is being loaded to this +alternate address. And this allows limited heap size. While +this is inevitable when exec'ing the interpreter directly, +we should do better for PIE applications. + +This fixes the loader to detect PIE application by checking if +elf_interpreter is requested. This images are loaded to beginning +of the address space instead of the specially crafted place for elf +interpreter. This allows full heap address space for PIE applications +and fixes random "out of memory" errors. + +Signed-off-by: Timo Teräs <timo.teras@iki.fi> +--- + fs/binfmt_elf.c | 14 ++++++-------- + 1 file changed, 6 insertions(+), 8 deletions(-) + +diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c +index 6f036ed..06419af 100644 +--- a/fs/binfmt_elf.c ++++ b/fs/binfmt_elf.c +@@ -1217,21 +1217,19 @@ static int load_elf_binary(struct linux_binprm *bprm) + * default mmap base, as well as whatever program they + * might try to exec. This is because the brk will + * follow the loader, and is not movable. */ ++ if (elf_interpreter) ++ load_bias = 0x00400000UL; ++ else ++ load_bias = ELF_ET_DYN_BASE; + #ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE + /* Memory randomization might have been switched off + * in runtime via sysctl or explicit setting of + * personality flags. +- * If that is the case, retain the original non-zero +- * load_bias value in order to establish proper +- * non-randomized mappings. + */ + if (current->flags & PF_RANDOMIZE) +- load_bias = 0; +- else +- load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr); +-#else +- load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr); ++ load_bias = (get_random_int() & STACK_RND_MASK) << PAGE_SHIFT; + #endif ++ load_bias = ELF_PAGESTART(load_bias - vaddr); + + #ifdef CONFIG_PAX_RANDMMAP + /* PaX: randomize base address at the default exe base if requested */ +-- +1.8.4 + + |