How to enable Stack Smashing Protection in pure swift application?
I did try to put "-fstack-protector-all" flag to Other C++ Flags under project build settings tab in xCode, but is seems that, this flag is unused or have no impact on builded application.
To verifie build I'm using otool -Iv AppBinary | grep stack
.
In Swift, Stack smashing is enabled by default one only need to add the "-fstack-protector-all" flag under build settings in objective-c applications.
How to check if stack smashing is enabled.
Run the otool command and presence of stack_chk_guard
and stack_chk_fail
means the code is stack smashing protected.
$ otool -Iv <appname>|grep stack
0x0013dfg 520 ___stack_chk_fail
0x001d009 521 ___stack_chk_guard
0x001fd345 520 ___stack_chk_fail
0x000000010087efd 513 ___stack_chk_fail
0x0000000100098hf3 514 ___stack_chk_guard
0x00000001000897gfr 513 ___stack_chk_fail
I was also facing this in my 100% Swift project.
Whenever I added -fstack-protector-all
to the "Other C-Flags" Build Settings the flags did not show up in the binary as described in the other comments.
What I did was to create an Objective-C Class…
// DummyClassForSSP.h
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface DummyClassForSSP : NSObject
+ (void)dummyCallSoFlagsShowUpInIPA;
@end
NS_ASSUME_NONNULL_END
… added a dummy implementation …
// DummyClassForSSP.m
#import "DummyClassForSSP.h"
@implementation DummyClassForSSP
+ (void)dummyCallSoFlagsShowUpInIPA {}
@end
… and called it from my AppDelegate.
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
....
DummyClassForSSP.dummyCallSoFlagsShowUpInIPA()
...
}
After that the flags showed up as described.
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