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authorFranck Bui-Huu <fbuihuu@gmail.com>2007-10-17 02:30:24 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 11:43:01 -0400
commitd68c9d6ae8f1fdae7d998158adc5ee106a2f8ce6 (patch)
tree91f1aef562d7769d06453e9a60ef599bcb057ba0 /fs
parent96358de6bc2ab0bc5e8b44a8f3be4c9bf4a14e4f (diff)
Break ELF_PLATFORM and stack pointer randomization dependency
Currently arch_align_stack() is used by fs/binfmt_elf.c to randomize stack pointer inside a page. But this happens only if ELF_PLATFORM symbol is defined. ELF_PLATFORM is normally set if the architecture wants ld.so to load implementation specific libraries for optimization. And currently a lot of architectures just yield this symbol to NULL. This is the case for MIPS architecture where ELF_PLATFORM is NULL but arch_align_stack() has been redefined to do stack inside page randomization. So in this case no randomization is actually done. This patch breaks this dependency which seems to be useless and allows platforms such MIPS to do the randomization. Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/binfmt_elf.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0f55b71ed983..6e2f3b8dde7f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -151,6 +151,14 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
151 struct vm_area_struct *vma; 151 struct vm_area_struct *vma;
152 152
153 /* 153 /*
154 * In some cases (e.g. Hyper-Threading), we want to avoid L1
155 * evictions by the processes running on the same package. One
156 * thing we can do is to shuffle the initial stack for them.
157 */
158
159 p = arch_align_stack(p);
160
161 /*
154 * If this architecture has a platform capability string, copy it 162 * If this architecture has a platform capability string, copy it
155 * to userspace. In some cases (Sparc), this info is impossible 163 * to userspace. In some cases (Sparc), this info is impossible
156 * for userspace to get any other way, in others (i386) it is 164 * for userspace to get any other way, in others (i386) it is
@@ -160,14 +168,6 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
160 if (k_platform) { 168 if (k_platform) {
161 size_t len = strlen(k_platform) + 1; 169 size_t len = strlen(k_platform) + 1;
162 170
163 /*
164 * In some cases (e.g. Hyper-Threading), we want to avoid L1
165 * evictions by the processes running on the same package. One
166 * thing we can do is to shuffle the initial stack for them.
167 */
168
169 p = arch_align_stack(p);
170
171 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len); 171 u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
172 if (__copy_to_user(u_platform, k_platform, len)) 172 if (__copy_to_user(u_platform, k_platform, len))
173 return -EFAULT; 173 return -EFAULT;