samples/ftrace: Mark my_tramp[12]? global

my_tramp[12]? are declared as global functions in C, but they are not marked global in the inline assembly definition. This mismatch confuses Clang's Control-Flow Integrity checking. Fix the definitions by adding .globl. Link: https://lkml.kernel.org/r/[email protected] Fixes: 9d907f1 ("ftrace/samples: Add a sample module that implements modify_ftrace_direct()") Reviewed-by: Kees Cook <[email protected]> Signed-off-by: Sami Tolvanen <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
marcan · Dec 1, 2020 · 983df5f · 983df5f
1 parent 8785f51
commit 983df5f
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Showing 3 changed files with 4 additions and 0 deletions.
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
@@ -21,6 +21,7 @@ static unsigned long my_ip = (unsigned long)schedule;
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp1, @function\n"
+"	.globl		my_tramp1\n"
 "   my_tramp1:"
 "	pushq %rbp\n"
 "	movq %rsp, %rbp\n"
@@ -29,6 +30,7 @@ asm (
 "	.size		my_tramp1, .-my_tramp1\n"
 "	ret\n"
 "	.type		my_tramp2, @function\n"
+"	.globl		my_tramp2\n"
 "   my_tramp2:"
 "	pushq %rbp\n"
 "	movq %rsp, %rbp\n"

diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
@@ -16,6 +16,7 @@ extern void my_tramp(void *);
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp, @function\n"
+"	.globl		my_tramp\n"
 "   my_tramp:"
 "	pushq %rbp\n"
 "	movq %rsp, %rbp\n"

diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
@@ -14,6 +14,7 @@ extern void my_tramp(void *);
 asm (
 "	.pushsection    .text, \"ax\", @progbits\n"
 "	.type		my_tramp, @function\n"
+"	.globl		my_tramp\n"
 "   my_tramp:"
 "	pushq %rbp\n"
 "	movq %rsp, %rbp\n"