mcount: Fix Unchecked Return Value in mcount_setup_trampoline()

Fixed: #498 Signed-off-by: GwanYeong Kim <gy741.kim@gmail.com>
namhyung · Sep 17, 2018 · fa88fef · fa88fef
1 parent 1db6a8b
commit fa88fef
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/arch/i386/mcount-dynamic.c b/arch/i386/mcount-dynamic.c
@@ -20,6 +20,7 @@ int mcount_setup_trampoline(struct mcount_dynamic_info *mdi)
 	unsigned char trampoline[] = { 0xe8, 0x00, 0x00, 0x00, 0x00, 0x58, 0xff, 0x60, 0x04 };
 	unsigned long fentry_addr = (unsigned long)__fentry__;
 	size_t trampoline_size = 16;
+	void *trampoline_check;
 
 	/* find unused 16-byte at the end of the code segment */
 	mdi->trampoline = ALIGN(mdi->text_addr + mdi->text_size, PAGE_SIZE) - trampoline_size;
@@ -31,8 +32,13 @@ int mcount_setup_trampoline(struct mcount_dynamic_info *mdi)
 		pr_dbg2("adding a page for fentry trampoline at %#lx\n",
 			mdi->trampoline);
 
-		mmap((void *)mdi->trampoline, PAGE_SIZE, PROT_READ | PROT_WRITE,
-		     MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+		trampoline_check = mmap((void *)mdi->trampoline, PAGE_SIZE,
+					PROT_READ | PROT_WRITE,
+		     			MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
+					-1, 0);
+
+		if (trampoline_check == MAP_FAILED)
+			pr_err("failed to mmap trampoline for setup");
 	}
 
 	if (mprotect((void *)mdi->text_addr, mdi->text_size, PROT_READ | PROT_WRITE)) {

diff --git a/arch/x86_64/mcount-dynamic.c b/arch/x86_64/mcount-dynamic.c
@@ -38,6 +38,7 @@ int mcount_setup_trampoline(struct mcount_dynamic_info *mdi)
 	unsigned long xray_exit_addr = (unsigned long)__xray_exit;
 	struct arch_dynamic_info *adi = mdi->arch;
 	size_t trampoline_size = 16;
+	void *trampoline_check;
 
 	if (adi && adi->xrmap_count)
 		trampoline_size *= 2;
@@ -53,8 +54,13 @@ int mcount_setup_trampoline(struct mcount_dynamic_info *mdi)
 		pr_dbg2("adding a page for fentry trampoline at %#lx\n",
 			mdi->trampoline);
 
-		mmap((void *)mdi->trampoline, PAGE_SIZE, PROT_READ | PROT_WRITE,
-		     MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+		trampoline_check = mmap((void *)mdi->trampoline, PAGE_SIZE,
+					PROT_READ | PROT_WRITE,
+		     			MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
+					-1, 0);
+
+		if (trampoline_check == MAP_FAILED)
+			pr_err("failed to mmap trampoline for setup");
 	}
 
 	if (mprotect((void *)mdi->text_addr, mdi->text_size, PROT_READ | PROT_WRITE)) {