[PATCH v10 09/12] kernel, arm64: untag user pointers in prctl_set_mm*

[Andrey Konovalov]

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 <andreyk...@google.com>
---
 kernel/sys.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kernel/sys.c b/kernel/sys.c
index f7eb62eceb24..12910be94b7f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1992,6 +1992,18 @@ 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;
@@ -2105,6 +2117,8 @@ 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.rc0.258.g878e2cd30e-goog