Bug 1732512 - Xvnc server crashed by tk-based application.
Summary: Xvnc server crashed by tk-based application.
Alias: None
Product: Fedora
Classification: Fedora
Component: xorg-x11-server
Version: 30
Hardware: x86_64
OS: Linux
Target Milestone: ---
Assignee: X/OpenGL Maintenance List
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2019-07-23 14:05 UTC by Paweł Sikora
Modified: 2020-05-26 18:10 UTC (History)
15 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
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Clone Of:
Last Closed: 2020-05-26 18:10:58 UTC
Type: Bug

Attachments (Terms of Use)

Description Paweł Sikora 2019-07-23 14:05:19 UTC
i've noticed that some 3rd-party tk-based application causing a tigervnc-server-1.9.0-4.fc30.x86_64 server crash.
as you can see the tigervnc passes to memcpy negatice __len value.

(gdb) fr 1
#1  0x000056043df40e79 in memcpy (__len=18446744073709551528, __src=<optimized out>, __dest=<optimized out>) at /usr/include/bits/string_fortified.h:34
warning: Source file is more recent than executable.
34        return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
(gdb) p/x __len
$1 = 0xffffffffffffffa8

% gdb /usr/bin/Xvnc --core core.8583 
GNU gdb (GDB) Fedora 8.3-6.fc30
Reading symbols from /usr/bin/Xvnc...
Reading symbols from /usr/lib/debug/usr/bin/Xvnc-1.9.0-4.fc30.x86_64.debug...
Core was generated by `/usr/bin/Xvnc'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  __memmove_avx_unaligned_erms () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:534
534             VMOVU   -(VEC_SIZE * 2)(%rcx), %VEC(2)
[Current thread is 1 (Thread 0x7fc91ca2cb40 (LWP 8583))]

(gdb) bt
#0  __memmove_avx_unaligned_erms () at ../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:534
#1  0x000056043df40e79 in memcpy (__len=18446744073709551528, __src=<optimized out>, __dest=<optimized out>) at /usr/include/bits/string_fortified.h:34
#2  fbBlt (srcLine=<optimized out>, srcStride=srcStride@entry=1004, srcX=<optimized out>, dstLine=<optimized out>, dstStride=dstStride@entry=1004, dstX=<optimized out>, width=-704, height=113, alu=3, 
    pm=4294967295, bpp=32, reverse=1, upsidedown=0) at fbblt.c:82
#3  0x000056043df4e13d in fbCopyNtoN (pSrcDrawable=pSrcDrawable@entry=0x56044031c970, pDstDrawable=pDstDrawable@entry=0x56044031c970, pGC=pGC@entry=0x56043e5a3f20, pbox=0x7ffd783e89c0, nbox=<optimized out>, 
    nbox@entry=1, dx=dx@entry=-218, dy=0, reverse=1, upsidedown=0, bitplane=0, closure=0x0) at fbcopy.c:69
#4  0x000056043e099993 in miCopyRegion (pSrcDrawable=pSrcDrawable@entry=0x56044031c970, pDstDrawable=pDstDrawable@entry=0x56044031c970, pGC=pGC@entry=0x56043e5a3f20, pDstRegion=pDstRegion@entry=0x7ffd783e89c0, 
    dx=dx@entry=-218, dy=dy@entry=0, copyProc=0x56043df4def0 <fbCopyNtoN>, bitPlane=0, closure=0x0) at micopy.c:121
#5  0x000056043e09a0f6 in miDoCopy (pSrcDrawable=0x56044031c970, pDstDrawable=0x56044031c970, pGC=0x56043e5a3f20, xIn=552, yIn=39, widthSrc=65514, heightSrc=113, xOut=770, yOut=39, 
    copyProc=0x56043df4def0 <fbCopyNtoN>, bitPlane=0, closure=0x0) at micopy.c:296
#6  0x000056043df4e726 in fbCopyArea (pSrcDrawable=<optimized out>, pDstDrawable=<optimized out>, pGC=<optimized out>, xIn=<optimized out>, yIn=<optimized out>, widthSrc=<optimized out>, heightSrc=113, 
    xOut=770, yOut=39) at fbcopy.c:244
#7  0x000056043dfc3ef6 in damageCopyArea (pSrc=0x56044031c970, pDst=0x56044031c970, pGC=0x56043e5a3f20, srcx=<optimized out>, srcy=<optimized out>, width=65514, height=113, dstx=770, dsty=39) at damage.c:775
#8  0x000056043e05b55d in ProcCopyArea (client=0x56043e63b420) at dispatch.c:1721
#9  0x000056043e05fabb in Dispatch () at dispatch.c:478
#10 0x000056043e063b04 in dix_main (argc=17, argv=0x7ffd783e8cd8, envp=<optimized out>) at main.c:276
#11 0x00007fc91d1c2f33 in __libc_start_main (main=0x56043df3a790 <main>, argc=17, argv=0x7ffd783e8cd8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd783e8cc8)
    at ../csu/libc-start.c:308
#12 0x000056043df3be7e in _start () at dispatch.c:357

Comment 1 Jan Grulich 2019-08-13 11:00:54 UTC
Upstream says it's an issue in Xorg server.

Upstream bug: https://github.com/TigerVNC/tigervnc/issues/853

Comment 2 Ben Cotton 2020-04-30 20:32:22 UTC
This message is a reminder that Fedora 30 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora 30 on 2020-05-26.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
Fedora 'version' of '30'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

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able to fix it before Fedora 30 is end of life. If you would still like 
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version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
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Comment 3 Ben Cotton 2020-05-26 18:10:58 UTC
Fedora 30 changed to end-of-life (EOL) status on 2020-05-26. Fedora 30 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
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