From: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Sun, 24 Jul 2016 15:30:22 +0000 (-0400)
Subject: binfmt_flat: use proper user space accessors with old relocs code
X-Git-Tag: v4.14-rc1~2718^2~5
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1b2ce442ea96b1e76300553963154d68cc5b4ad0;p=platform%2Fkernel%2Flinux-rpi.git

binfmt_flat: use proper user space accessors with old relocs code

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
---

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 9deafb2..8e812d7 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -379,35 +379,38 @@ static void old_reloc(unsigned long rl)
 {
 	static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
 	flat_v2_reloc_t	r;
-	unsigned long *ptr;
+	unsigned long __user *ptr;
+	unsigned long val;
 
 	r.value = rl;
 #if defined(CONFIG_COLDFIRE)
-	ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
+	ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset);
 #else
-	ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
+	ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset);
 #endif
+	get_user(val, ptr);
 
 	pr_debug("Relocation of variable at DATASEG+%x "
 		 "(address %p, currently %lx) into segment %s\n",
-		 r.reloc.offset, ptr, *ptr, segment[r.reloc.type]);
+		 r.reloc.offset, ptr, val, segment[r.reloc.type]);
 
 	switch (r.reloc.type) {
 	case OLD_FLAT_RELOC_TYPE_TEXT:
-		*ptr += current->mm->start_code;
+		val += current->mm->start_code;
 		break;
 	case OLD_FLAT_RELOC_TYPE_DATA:
-		*ptr += current->mm->start_data;
+		val += current->mm->start_data;
 		break;
 	case OLD_FLAT_RELOC_TYPE_BSS:
-		*ptr += current->mm->end_data;
+		val += current->mm->end_data;
 		break;
 	default:
 		pr_err("Unknown relocation type=%x\n", r.reloc.type);
 		break;
 	}
+	put_user(val, ptr);
 
-	pr_debug("Relocation became %lx\n", *ptr);
+	pr_debug("Relocation became %lx\n", val);
 }
 
 /****************************************************************************/
@@ -780,8 +783,13 @@ static int load_flat_file(struct linux_binprm *bprm,
 			}
 		}
 	} else {
-		for (i = 0; i < relocs; i++)
-			old_reloc(ntohl(reloc[i]));
+		for (i = 0; i < relocs; i++) {
+			unsigned long relval;
+			if (get_user(relval, reloc + i))
+				return -EFAULT;
+			relval = ntohl(relval);
+			old_reloc(relval);
+		}
 	}
 
 	flush_icache_range(start_code, end_code);