This patch is a part of a series that extends arm64 kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. prctl_set_mm() and prctl_set_mm_map() use provided user pointers for vma lookups, which can only by done with untagged pointers. Untag user pointers in these functions. Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> --- kernel/sys.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/sys.c b/kernel/sys.c index 12df0e5434b8..8e56d87cc6db 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1993,6 +1993,18 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data if (copy_from_user(&prctl_map, addr, sizeof(prctl_map))) return -EFAULT; + prctl_map->start_code = untagged_addr(prctl_map.start_code); + prctl_map->end_code = untagged_addr(prctl_map.end_code); + prctl_map->start_data = untagged_addr(prctl_map.start_data); + prctl_map->end_data = untagged_addr(prctl_map.end_data); + prctl_map->start_brk = untagged_addr(prctl_map.start_brk); + prctl_map->brk = untagged_addr(prctl_map.brk); + prctl_map->start_stack = untagged_addr(prctl_map.start_stack); + prctl_map->arg_start = untagged_addr(prctl_map.arg_start); + prctl_map->arg_end = untagged_addr(prctl_map.arg_end); + prctl_map->env_start = untagged_addr(prctl_map.env_start); + prctl_map->env_end = untagged_addr(prctl_map.env_end); + error = validate_prctl_map(&prctl_map); if (error) return error; @@ -2106,6 +2118,8 @@ static int prctl_set_mm(int opt, unsigned long addr, opt != PR_SET_MM_MAP_SIZE))) return -EINVAL; + addr = untagged_addr(addr); + #ifdef CONFIG_CHECKPOINT_RESTORE if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE) return prctl_set_mm_map(opt, (const void __user *)addr, arg4); -- 2.21.0.360.g471c308f928-goog
