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Diffstat (limited to 'results/classifier/zero-shot-user-mode/output/instruction/1749393')
| -rw-r--r-- | results/classifier/zero-shot-user-mode/output/instruction/1749393 | 32 |
1 files changed, 0 insertions, 32 deletions
diff --git a/results/classifier/zero-shot-user-mode/output/instruction/1749393 b/results/classifier/zero-shot-user-mode/output/instruction/1749393 deleted file mode 100644 index 66645885..00000000 --- a/results/classifier/zero-shot-user-mode/output/instruction/1749393 +++ /dev/null @@ -1,32 +0,0 @@ -instruction: 0.613 -runtime: 0.288 -syscall: 0.099 - - - -sbrk() not working under qemu-user with a PIE-compiled binary? - -In Debian unstable, we recently switched bash to be a PIE-compiled binary (for hardening). Unfortunately this resulted in bash being broken when run under qemu-user (for all target architectures, host being amd64 for me). - -$ sudo chroot /srv/chroots/sid-i386/ qemu-i386-static /bin/bash -bash: xmalloc: .././shell.c:1709: cannot allocate 10 bytes (0 bytes allocated) - -bash has its own malloc implementation based on sbrk(): -https://git.savannah.gnu.org/cgit/bash.git/tree/lib/malloc/malloc.c - -When we disable this internal implementation and rely on glibc's malloc, then everything is fine. But it might be that glibc has a fallback when sbrk() is not working properly and it might hide the underlying problem in qemu-user. - -This issue has also been reported to the bash upstream author and he suggested that the issue might be in qemu-user so I'm opening a ticket here. Here's the discussion with the bash upstream author: -https://lists.gnu.org/archive/html/bug-bash/2018-02/threads.html#00080 - -You can find the problematic bash binary in that .deb file: -http://snapshot.debian.org/archive/debian/20180206T154716Z/pool/main/b/bash/bash_4.4.18-1_i386.deb - -The version of qemu I have been using is 2.11 (Debian package qemu-user-static version 1:2.11+dfsg-1) but I have had reports that the problem is reproducible with older versions (back to 2.8 at least). - -Here are the related Debian bug reports: -https://bugs.debian.org/889869 -https://bugs.debian.org/865599 - -It's worth noting that bash used to have this problem (when compiled as a PIE binary) even when run directly but then something got fixed in the kernel and now the problem only appears when run under qemu-user: -https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1518483
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