AddressSanitizer reports heap-buffer-overflow DRImagePlaceholderHelper.m:151

[phoney]

There is a problem where a fillColor is [UIColor lightGreyColor] and imageCachedForSize:isAvatar:fillColor:text: assumes there are four components to the UIColor but there are only two.

This happens from placerholderImageWithSize: where the fillColor is hard-coded to [UIColor lightGrayColor].

To reproduce this:

Open the Example project
Edit the Scheme (I'm using iPhone 7 Plus (10.0))
Run > Diagnostics - check the box to enable Address Sanitizer
Launch the Example
It will stop pretty quickly with the error message I mentioned and the following text in the console

=================================================================
==40294==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x607000030900 at pc 0x00010de3075c bp 0x7fff51dd2b90 sp 0x7fff51dd2b88
READ of size 8 at 0x607000030900 thread T0
#0 0x10de3075b in -[DRImagePlaceholderHelper imageCachedForSize:isAvatar:fillColor:text:] DRImagePlaceholderHelper.m:151
#1 0x10de2f91f in -[DRImagePlaceholderHelper placerholderImageWithSize:text:fillColor:] DRImagePlaceholderHelper.m:111
#2 0x10de2ee4b in -[DRImagePlaceholderHelper placerholderImageWithSize:fillColor:] DRImagePlaceholderHelper.m:99
#3 0x10de2e85c in -[DRImagePlaceholderHelper placerholderImageWithSize:] DRImagePlaceholderHelper.m:92
#4 0x10de2ae74 in -[UIImageView(Placeholder) fillWithPlaceholderImage] UIImageView+Placeholder.m:16
#5 0x10de326b8 in -[ViewController viewDidLoad] ViewController.m:22
#6 0x10f50406c in -[UIViewController loadViewIfRequired] (UIKit+0x1c906c)
#7 0x10f50449f in -[UIViewController view] (UIKit+0x1c949f)
#8 0x10f3ce044 in -[UIWindow addRootViewControllerViewIfPossible] (UIKit+0x93044)
#9 0x10f3ce795 in -[UIWindow _setHidden:forced:] (UIKit+0x93795)
#10 0x10f3e20a8 in -[UIWindow makeKeyAndVisible] (UIKit+0xa70a8)
#11 0x10f35b258 in -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] (UIKit+0x20258)
#12 0x10f3613b8 in -[UIApplication _runWithMainScene:transitionContext:completion:] (UIKit+0x263b8)
#13 0x10f35e538 in -[UIApplication workspaceDidEndTransaction:] (UIKit+0x23538)
#14 0x11434276a in FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK (FrontBoardServices+0x3b76a)
#15 0x1143425e3 in -[FBSSerialQueue _performNext] (FrontBoardServices+0x3b5e3)
#16 0x11434296c in -[FBSSerialQueue _performNextFromRunLoopSource] (FrontBoardServices+0x3b96c)
#17 0x111a6e310 in CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION (CoreFoundation+0x9c310)
#18 0x111a5359b in __CFRunLoopDoSources0 (CoreFoundation+0x8159b)
#19 0x111a52a85 in __CFRunLoopRun (CoreFoundation+0x80a85)
#20 0x111a52493 in CFRunLoopRunSpecific (CoreFoundation+0x80493)
#21 0x10f35cdb5 in -[UIApplication _run] (UIKit+0x21db5)
#22 0x10f362f33 in UIApplicationMain (UIKit+0x27f33)
#23 0x10de3189e in main main.m:16
#24 0x110ea168c in start (libdyld.dylib+0x468c)

0x607000030900 is located 0 bytes to the right of 80-byte region [0x6070000308b0,0x607000030900)
allocated by thread T0 here:
#0 0x10defdbd0 in __sanitizer_mz_malloc (libclang_rt.asan_iossim_dynamic.dylib+0x49bd0)
#1 0x1129248d1 in malloc_zone_malloc (libsystem_malloc.dylib+0xe8d1)
#2 0x1119d5a56 in _CFRuntimeCreateInstance (CoreFoundation+0x3a56)
#3 0x10f0632d4 in CGTypeCreateInstance (CoreGraphics+0x4382d4)
#4 0x10eeb833e in create_color (CoreGraphics+0x28d33e)
#5 0x10f67a061 in -[UIDeviceWhiteColor _createCGColorWithAlpha:] (UIKit+0x33f061)
#6 0x10f67a454 in -[UIDeviceWhiteColor CGColor] (UIKit+0x33f454)
#7 0x10de3066b in -[DRImagePlaceholderHelper imageCachedForSize:isAvatar:fillColor:text:] DRImagePlaceholderHelper.m:150
#8 0x10de2f91f in -[DRImagePlaceholderHelper placerholderImageWithSize:text:fillColor:] DRImagePlaceholderHelper.m:111
#9 0x10de2ee4b in -[DRImagePlaceholderHelper placerholderImageWithSize:fillColor:] DRImagePlaceholderHelper.m:99
#10 0x10de2e85c in -[DRImagePlaceholderHelper placerholderImageWithSize:] DRImagePlaceholderHelper.m:92
#11 0x10de2ae74 in -[UIImageView(Placeholder) fillWithPlaceholderImage] UIImageView+Placeholder.m:16
#12 0x10de326b8 in -[ViewController viewDidLoad] ViewController.m:22
#13 0x10f50406c in -[UIViewController loadViewIfRequired] (UIKit+0x1c906c)
#14 0x10f50449f in -[UIViewController view] (UIKit+0x1c949f)
#15 0x10f3ce044 in -[UIWindow addRootViewControllerViewIfPossible] (UIKit+0x93044)
#16 0x10f3ce795 in -[UIWindow _setHidden:forced:] (UIKit+0x93795)
#17 0x10f3e20a8 in -[UIWindow makeKeyAndVisible] (UIKit+0xa70a8)
#18 0x10f35b258 in -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] (UIKit+0x20258)
#19 0x10f3613b8 in -[UIApplication _runWithMainScene:transitionContext:completion:] (UIKit+0x263b8)
#20 0x10f35e538 in -[UIApplication workspaceDidEndTransaction:] (UIKit+0x23538)
#21 0x11434276a in FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK (FrontBoardServices+0x3b76a)
#22 0x1143425e3 in -[FBSSerialQueue _performNext] (FrontBoardServices+0x3b5e3)
#23 0x11434296c in -[FBSSerialQueue _performNextFromRunLoopSource] (FrontBoardServices+0x3b96c)
#24 0x111a6e310 in CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION (CoreFoundation+0x9c310)
#25 0x111a5359b in __CFRunLoopDoSources0 (CoreFoundation+0x8159b)
#26 0x111a52a85 in __CFRunLoopRun (CoreFoundation+0x80a85)
#27 0x111a52493 in CFRunLoopRunSpecific (CoreFoundation+0x80493)
#28 0x10f35cdb5 in -[UIApplication _run] (UIKit+0x21db5)
#29 0x10f362f33 in UIApplicationMain (UIKit+0x27f33)

SUMMARY: AddressSanitizer: heap-buffer-overflow DRImagePlaceholderHelper.m:151 in -[DRImagePlaceholderHelper imageCachedForSize:isAvatar:fillColor:text:]
Shadow bytes around the buggy address:
0x1c0e000060d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e000060e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e000060f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00006100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x1c0e00006110: fa fa fa fa fa fa 00 00 00 00 00 00 00 00 00 00
=>0x1c0e00006120:[fa]fa fa fa 00 00 00 00 00 00 00 00 00 00 fa fa
0x1c0e00006130: fa fa 00 00 00 00 00 00 00 00 00 00 fa fa fa fa
0x1c0e00006140: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa 00 00
0x1c0e00006150: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00
0x1c0e00006160: 00 00 00 00 00 00 fa fa fa fa 00 00 00 00 00 00
0x1c0e00006170: 00 00 00 00 fa fa fa fa 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==40294==ABORTING
AddressSanitizer report breakpoint hit. Use 'thread info -s' to get extended information about the report.

[phoney]

This is the fix if anyone cares:

• (NSString*)colorAsString:(UIColor*)color
  {
  const CGFloat *componentsP = CGColorGetComponents(color.CGColor);
  NSInteger count = MIN(CGColorGetNumberOfComponents(color.CGColor), 4);
  CGFloat components[4] = { 0, 0, 0, 0 };

  for (NSInteger i = 0; i < count; i++) {
  components[i] = componentsP[i];
  }

  NSString *colorAsString = [NSString stringWithFormat:@"%f,%f,%f,%f", components[0], components[1], components[2], components[3]];

  return colorAsString;
  }
  And call it like
  NSString *colorAsString = [self colorAsString:color];
  from both
  imageCachedForSize:isAvatar:fillColor:text:
  and
  cacheImage: isAvatar: fillColor:text: