Fix crash due to unexpected fonts methods.

[arandomdev]

In twitter 9.47 there are some methods in TAEStandardFontGroup that have arguments,

fontOfSize:
mediumFontOfSize:
boldFontOfSize:
heavyFontOfSize:
monospacedDigitFontOfSize:weight:

The method that these are replaced with don't seem to handle them, so I added a small check to filter these methods out. This has also fixed the crash in #129 for me.

Also, I'm assuming the target methods are like,

- (id)subtext1MediumFont;
- (id)subtext1BoldFont;
- (id)bodyFont;

and don't include methods like,

- (void)_tae_resetFont_subtext3Font;
- (void)_tae_resetFont_subtext3MediumFont;
- (void)_tae_resetFont_subtext3BoldFont;
- (void)_tae_resetFont_subtext2Font;

If so, I believe a better method would be to filter by method type encodings. We would be looking for methods with the following type encoding, @@:. Please let me know if I should use that instead.

[BandarHL]

Thank for the PR. I’m thinking your code is enough but I’m gonna look more on it

[BandarHL]

We can use method_getReturnType for accurate results.

[arandomdev]

That could work, but it’ll include the methods that require arguments, since I believe fontOfSize: also returns id. I suggested type encoding as it would include both the return type and arguments. For @@: it would return an object and have 2 arguments, an object (self) and a selector.

[BandarHL]

The idea here is just accept methods that have a return type otherwise ignore it

[BandarHL]

and for the size of font in the args, we don't need it because when we take the return value (UIFont) we can take size from the UIFont class

[arandomdev]

Unfortunately it seems to crash again with the changes. I can try to look into passing additional arguments and open another PR.

[BandarHL]

And what is the crash log?

[BandarHL]

I'm afraid the problem is from the version of the IPA I was used. check this one: https://drive.google.com/file/d/1p-AWS-yPa4gvCLSn2sC5wKcJZagRUhgh/view?usp=share_link

[BandarHL]

it seems to work fine

[arandomdev]

Yep it still crashes, here is my crash log from earlier. Twitter-2023-03-05-141735.zip

It might be because my iOS version has an extra check? I'm on iOS15.1.

[BandarHL]

Are you sure the issue is from the Font? because I tried with a trollSore device (15.0) with disabled Font feature and the crash is still

[BandarHL]

and with a crash log there is no mention to BHTwitter process

[arandomdev]

I think so, commenting out the TAEStandardFontGroup hook, the crashing stops. And I believe that azule directly injects it into the main app, so it doesn't load any dylibs.

[BandarHL]

and why the crash just for trollstore

[BandarHL]

Maybe the problem for just 15-15.1? https://twitter.com/omega_omelet/status/1632540333505658880

[arandomdev]

Maybe? Right now I'm trying to just forward the arguments to see if that will work.

It fixes the crashes and custom fonts still work.

[BandarHL]

okay since that fix the problem i'm going to try pass all args. Im sure there is a way in Runtime library

[BandarHL]

After researching, we have two options either ignore methods that have args or pass it throw the replacements. and the best option here is just to ignore it.

[BandarHL]

Try this code

%hook TAEStandardFontGroup
+ (TAEStandardFontGroup *)sharedFontGroup {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        NSMutableArray *fontsMethods = [NSMutableArray arrayWithArray:@[]];

        unsigned int methodCount = 0;
        Method *methods = class_copyMethodList([self class], &methodCount);
        for (unsigned int i = 0; i < methodCount; ++i) {
            Method method = methods[i];
            char returnType[255];
            char methodType[255];
            method_getReturnType(method, returnType, 255);
            method_getArgumentType(method, i, methodType, 255);
            const char *name = sel_getName(method_getName(method));
            NSString *selector = [NSString stringWithUTF8String:name];

            // Just add methods that have return type.
            if ([@(returnType) containsString:@"@"] && ![@(methodType) containsString:@"@"]) {
                [fontsMethods addObject:selector];
            }
        }
        free(methods);

        originalFontsIMP = [NSMutableDictionary new];
        batchSwizzlingOnClass([self class], [fontsMethods copy], (IMP)TAEStandardFontGroupReplacement);
    });
    return %orig;
}
%end

[arandomdev]

I found a way to pass additional arguments. As long as we don't try access any arguments that aren't there, it should be fine.

Custom fonts still seem to work, I'll quickly upload this for you to test.

[arandomdev]

Hmm git doesn't like what I did. I'll just make another PR.