darling-dmg issue with Fedora 25 (findLeafNode() crashing when in debug mode)

[jeanthom]

Hi !

I've been trying to get darling-dmg working under Fedora 25. I currently run into two issue :

• darling-dmg, when normally run (darling-dmg mydmg.dmg /mnt/mountpoint), ends abruplty
• trying to sort things in debug mode, I ran darling-dmg in debug mode and got a SIGSEGV. I compiled it again with debug info and ran it in GDB :

(gdb) run testimg.dmg /tmp/atvos -d
Starting program: /home/jeanthomas/Applications/darling-dmg/darling-dmg testimg.dmg /tmp/atvos -d
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Skipping partition of type Apple_partition_map
Using partition #1 of type Apple_HFS
Everything looks OK, disk mounted
Detaching after fork from child process 27709.
FUSE library version: 2.9.7
nullpath_ok: 0
nopath: 0
utime_omit_ok: 0
unique: 1, opcode: INIT (26), nodeid: 0, insize: 56, pid: 0
INIT: 7.26
flags=0x001ffffb
max_readahead=0x00020000
   INIT: 7.19
   flags=0x00000011
   max_readahead=0x00020000
   max_write=0x00020000
   max_background=0
   congestion_threshold=0
   unique: 1, success, outsize: 40
unique: 2, opcode: ACCESS (34), nodeid: 1, insize: 48, pid: 1891
   unique: 2, error: -38 (Function not implemented), outsize: 16
unique: 3, opcode: LOOKUP (1), nodeid: 1, insize: 47, pid: 1891
LOOKUP /.Trash
getattr /.Trash
hfs_getattr(/.Trash)
File not found: /.Trash
   unique: 3, error: -2 (No such file or directory), outsize: 16
unique: 4, opcode: LOOKUP (1), nodeid: 1, insize: 52, pid: 1891
LOOKUP /.Trash-1000
getattr /.Trash-1000
hfs_getattr(/.Trash-1000)
File not found: /.Trash-1000
   unique: 4, error: -2 (No such file or directory), outsize: 16
unique: 5, opcode: GETATTR (3), nodeid: 1, insize: 56, pid: 27725
getattr /
hfs_getattr(/)
   unique: 5, success, outsize: 120
unique: 6, opcode: OPENDIR (27), nodeid: 1, insize: 48, pid: 27741
   unique: 6, success, outsize: 32
unique: 7, opcode: READDIR (28), nodeid: 1, insize: 80, pid: 27741
readdir[0] from 0
hfs_readdir(/)
   unique: 7, success, outsize: 888
unique: 8, opcode: LOOKUP (1), nodeid: 1, insize: 53, pid: 27741
LOOKUP /Applications
getattr /Applications
hfs_getattr(/Applications)
   NODEID: 2
   unique: 8, success, outsize: 144
unique: 9, opcode: LOOKUP (1), nodeid: 1, insize: 51, pid: 27741
LOOKUP /Desktop DB
getattr /Desktop DB
hfs_getattr(/Desktop DB)
   NODEID: 3
   unique: 9, success, outsize: 144
unique: 10, opcode: GETXATTR (22), nodeid: 3, insize: 68, pid: 27741
getxattr /Desktop DB security.capability 20
hfs_getxattr(/Desktop DB, security.capability)

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff795cc1b in HFSBTree::findLeafNode (this=0x0, indexKey=0x7fffffffd3e0, comp=0x7ffff7968cba <HFSAttributeBTree::cnidAttrComparator(HFSBTree::Key const*, HFSBTree::Key const*)>, 
    wildcard=false) at /home/jeanthomas/Applications/darling-dmg/src/HFSBTree.cpp:45
45		return traverseTree(be(m_header.rootNode), indexKey, comp, wildcard);
(gdb) bt
#0  0x00007ffff795cc1b in HFSBTree::findLeafNode (this=0x0, indexKey=0x7fffffffd3e0, comp=0x7ffff7968cba <HFSAttributeBTree::cnidAttrComparator(HFSBTree::Key const*, HFSBTree::Key const*)>, 
    wildcard=false) at /home/jeanthomas/Applications/darling-dmg/src/HFSBTree.cpp:45
#1  0x00007ffff7968a3a in HFSAttributeBTree::getattr (this=0x0, cnid=19192, attrName="security.capability", dataOut=std::vector of length 0, capacity 0)
    at /home/jeanthomas/Applications/darling-dmg/src/HFSAttributeBTree.cpp:63
#2  0x00007ffff797ac2e in HFSHighLevelVolume::getXattr (this=0x6ec450, path="/Desktop DB", name="security.capability")
    at /home/jeanthomas/Applications/darling-dmg/src/HFSHighLevelVolume.cpp:257
#3  0x000000000040ee67 in <lambda()>::operator()(void) const (__closure=0x7f8b20) at /home/jeanthomas/Applications/darling-dmg/src/main-fuse.cpp:276
#4  0x000000000040ffb3 in std::_Function_handler<int(), hfs_getxattr(char const*, char const*, char*, size_t)::<lambda()> >::_M_invoke(const std::_Any_data &) (__functor=...)
    at /usr/include/c++/6.4.1/functional:1717
#5  0x000000000041136c in std::function<int ()>::operator()() const (this=0x7fffffffd990) at /usr/include/c++/6.4.1/functional:2127
#6  0x000000000040e194 in handle_exceptions(std::function<int ()>) (func=...) at /home/jeanthomas/Applications/darling-dmg/src/main-fuse.cpp:141
#7  0x000000000040f061 in hfs_getxattr (path=0x6ace00 "/Desktop DB", name=0x797b60 "security.capability", value=0x77f9a0 "Hk\v\366\377\177", vlen=20)
    at /home/jeanthomas/Applications/darling-dmg/src/main-fuse.cpp:283
#8  0x00007ffff7ba9fee in common_getxattr () from /lib64/libfuse.so.2
#9  0x00007ffff7baa0d7 in fuse_lib_getxattr () from /lib64/libfuse.so.2
#10 0x00007ffff7bb04c1 in fuse_ll_process_buf () from /lib64/libfuse.so.2
#11 0x00007ffff7bac86c in fuse_session_loop () from /lib64/libfuse.so.2
#12 0x00007ffff7ba4c18 in fuse_loop () from /lib64/libfuse.so.2
#13 0x00007ffff7bb5247 in fuse_main_common () from /lib64/libfuse.so.2
#14 0x000000000040d978 in main (argc=4, argv=0x7fffffffe088) at /home/jeanthomas/Applications/darling-dmg/src/main-fuse.cpp:70

[jeanthom]

I think I nailed the issue.

HFSHighLevelVolume::getXattr (this=0x64f120, path="/Desktop DB", name="security.capability") at /home/jeanthomas/Applications/darling-dmg/src/HFSHighLevelVolume.cpp:254
254			if (rv != 0)
(gdb) 
257			if (!m_volume->attributes()->getattr(ff.file.fileID, name, output))
(gdb) 

Program received signal SIGSEGV, Segmentation fault

Commenting if (!m_volume->attributes()->getattr(ff.file.fileID, name, output)) (HFSHighLevelVolume.cpp:254) solved my issue ! However that is definitively NOT a proper fix 😄