leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

arm64: compat: Poison the compat sigpage

Browse Source 
Commit 9c698bff66 ("ARM: ensure the signal page contains defined contents")
poisoned the unused portions of the signal page for 32-bit Arm.

Implement the same poisoning for the compat signal page on arm64 rather
than using __GFP_ZERO.

Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20210318170738.7756-6-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Will Deacon 2021-03-18 17:07:38 +00:00 committed by Catalin Marinas
parent 77ec462536
commit 6e554abd07
1 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/arm64/kernel/vdso.c
View File

@ -318,17 +318,20 @@ static int aarch32_alloc_kuser_vdso_page(void)
return 0; return 0;
} }
#define COMPAT_SIGPAGE_POISON_WORD 0xe7fddef1
static int aarch32_alloc_sigpage(void) static int aarch32_alloc_sigpage(void)
{ {
extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
unsigned long sigpage; __le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD);
void *sigpage;
sigpage = get_zeroed_page(GFP_KERNEL); sigpage = (void *)__get_free_page(GFP_KERNEL);
if (!sigpage) if (!sigpage)
return -ENOMEM; return -ENOMEM;
memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz); memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison));
memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz);
aarch32_sig_page = virt_to_page(sigpage); aarch32_sig_page = virt_to_page(sigpage);
return 0; return 0;
} }