[fuzzing] dagcbor Decode/Encode panic: index out of range

[bryanchriswhite]

Crasher

095da066af3e1b98946007a7e76901af4836f2cf

Quoted Input

        "\x8d\x8d\x97\xd8*@"

Output

panic: runtime error: index out of range [0] with length 0                                                  
goroutine 6 [running]:                                                                                      
runtime/debug.Stack(0xc000085660, 0x713920, 0xc00001ab20)                                                   
        /usr/local/go/src/runtime/debug/stack.go:24 +0x9f                                                   
github.com/leastauthority/fleece/fuzzing.(*Crasher).Recover(0xc00007f040, 0xc000195d70)                     
        /home/bwhite/go/pkg/mod/github.com/leastauthority/fleece@v0.0.1-alpha/fuzzing/crasher.go:23 +0x57   
panic(0x713920, 0xc00001ab20)                                                                               
        /usr/local/go/src/runtime/panic.go:969 +0x175                                                       
github.com/ipld/go-ipld-prime/codec/dagcbor.unmarshal(0x78fc00, 0xc00000ed48, 0x789960, 0xc0000a2500, 0xc000
1b6700, 0x0, 0xc0001b6700)                                                                                  
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/unmarshal.go:130 +0xb88                       
github.com/ipld/go-ipld-prime/codec/dagcbor.unmarshal(0x78fc00, 0xc00000ed08, 0x789960, 0xc0000a2500, 0xc000
1b6700, 0x0, 0xc0001b6700)                                                                                  
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/unmarshal.go:112 +0x1a8                       
github.com/ipld/go-ipld-prime/codec/dagcbor.unmarshal(0x78fc00, 0xc0000a24e0, 0x789960, 0xc0000a2500, 0xc000
1b6700, 0x0, 0xc0001b6700)                                                                                  
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/unmarshal.go:112 +0x1a8
github.com/ipld/go-ipld-prime/codec/dagcbor.unmarshal(0x7f064c709e18, 0xc0000a24b0, 0x789960, 0xc0000a2500, 
0xc0001b6700, 0x710740, 0x972c01)
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/unmarshal.go:112 +0x1a8
github.com/ipld/go-ipld-prime/codec/dagcbor.Unmarshal(0x7f064c709e18, 0xc0000a24b0, 0x789960, 0xc0000a2500, 
0x0, 0x40cf00)
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/unmarshal.go:33 +0xcc
github.com/ipld/go-ipld-prime/codec/dagcbor.Decoder(0x7f064c709e18, 0xc0000a24b0, 0x7897a0, 0xc0000ad7d0, 0x
c0000a24b0, 0x0)
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/multicodec.go:32 +0x1d2
github.com/ipld/go-ipld-prime/codec/dagcbor.FuzzCBORDecodeEncode(0xc0003386c0, 0x6, 0x206, 0x0)
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/multicodec_fuzz.go:16 +0xe8
github.com/leastauthority/fleece/fuzzing.(*Crasher).Test(0xc00007f040, 0xc000085d70)
        /home/bwhite/go/pkg/mod/github.com/leastauthority/fleece@v0.0.1-alpha/fuzzing/crasher.go:31 +0x7b
github.com/leastauthority/fleece/fuzzing.CrasherIterator.TestFailingLimit(0xc00007d150, 0x34, 0x11, 0xc00000
e800, 0x3, 0x4, 0xc000224000, 0x54c, 0x54c, 0x7468b0, ...)
        /home/bwhite/go/pkg/mod/github.com/leastauthority/fleece@v0.0.1-alpha/fuzzing/iterator.go:109 +0xf0
github.com/ipld/go-ipld-prime/codec/dagcbor.TestFuzzCBORDecodeEncode(0xc000001b00)
        /run/media/bwhite/1TB SSD/go-ipld-prime/codec/dagcbor/multicodec_fuzz_test.go:57 +0x171
testing.tRunner(0xc000001b00, 0x7468b8)
        /usr/local/go/src/testing/testing.go:1108 +0xef
created by testing.(*T).Run 
        /usr/local/go/src/testing/testing.go:1159 +0x386

[warpfork]

Put a tasty new fix for this on master just now, thanks for uncovering this :)

[schomatis]

ipld/go-ipld-prime@ec73de2

[bryanchriswhite]

Put a tasty new fix for this on master just now, thanks for uncovering this :)

Nice and of course! 😄