#298 Invalid Memory Read when calling processing jb2 images

[Hongxu Chen]

When running cjb2 $FILE /dev/null, it may trigger an invalid read error at JB2Image.h:741 or jb2tune.cpp:294.

ASAN:DEADLYSIGNAL
=================================================================
==10212==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000001 (pc 0x7f49de7949d2 bp 0x7ffccf4a33b0 sp 0x7ffccf4a3390 T0)
==10212==The signal is caused by a READ memory access.
==10212==Hint: address points to the zero page.
    #0 0x7f49de7949d1 in JB2Dict::JB2Codec::get_direct_context(unsigned char const*, unsigned char const*, unsigned char const*, int) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2Image.h:741
    #1 0x7f49de792ab4 in JB2Dict::JB2Codec::Encode::code_bitmap_directly(GBitmap&, int, int, unsigned char*, unsigned char*, unsigned char*) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2EncodeCodec.cpp:304
    #2 0x7f49de79b2a0 in JB2Dict::JB2Codec::code_bitmap_directly(GBitmap&) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2Image.cpp:815
    #3 0x7f49de79d78b in JB2Dict::JB2Codec::code_record(int&, GP<JB2Image> const&, JB2Shape*, JB2Blit*) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2Image.cpp:1143
    #4 0x7f49de793e2d in JB2Dict::JB2Codec::Encode::code(GP<JB2Image> const&) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2EncodeCodec.cpp:494
    #5 0x7f49de7950bd in JB2Dict::JB2Codec::Encode::code(JB2Image*) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2EncodeCodec.cpp:100
    #6 0x7f49de791fa8 in JB2Image::encode(GP<ByteStream> const&) const /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2EncodeCodec.cpp:152
    #7 0x557743e8b800 in cjb2(GURL const&, GURL const&, cjb2opts&) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/cjb2.cpp:894
    #8 0x557743e8c6c6 in main /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/cjb2.cpp:985
    #9 0x7f49dd585b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #10 0x557743e849d9 in _start (/home/hongxu/FOT/djvulibre/djvu-djvulibre-git/install/bin/cjb2+0x79d9)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/libdjvu/JB2Image.h:741 in JB2Dict::JB2Codec::get_direct_context(unsigned char const*, unsigned char const*, unsigned char const*, int)
==10212==ABORTING

or

ASAN:DEADLYSIGNAL
=================================================================
==15504==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000001 (pc 0x561a047508e4 bp 0x7fff7e880970 sp 0x7fff7e8808a0 T0)
==15504==The signal is caused by a READ memory access.
==15504==Hint: address points to the zero page.
    #0 0x561a047508e3 in tune_jb2image /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/jb2tune.cpp:294
    #1 0x561a04751078 in tune_jb2image_lossless(JB2Image*) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/jb2tune.cpp:377
    #2 0x561a0474928a in cjb2(GURL const&, GURL const&, cjb2opts&) /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/cjb2.cpp:864
    #3 0x561a0474a6c6 in main /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/cjb2.cpp:985
    #4 0x7f52a0787b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #5 0x561a047429d9 in _start (/home/hongxu/FOT/djvulibre/djvu-djvulibre-git/install/bin/cjb2+0x79d9)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/hongxu/FOT/djvulibre/djvu-djvulibre-git/tools/jb2tune.cpp:294 in tune_jb2image
==15504==ABORTING

This sometimes also affects the cpaldjvu utility.

[Hongxu Chen]

git commit version 23522feec1e200cd2981c8e063ce1ea3a333a14f (3.5.27)

[Leon Bottou]

Fixed.