bugGNU GRUB - Bugs: bug #51153, SYSLINUX config parsing is very...

 
 

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bug #51153: SYSLINUX config parsing is very fragile

Submitted by:  felix <felix_s>
Submitted on:  Thu 01 Jun 2017 10:00:20 AM UTC  
 
Category: NoneSeverity: Major
Priority: 5 - NormalItem Group: Software Error
Status: NonePrivacy: Public
Assigned to: NoneOriginator Name: 
Open/Closed: OpenRelease: 
Release: Git masterReproducibility: Every Time
Planned Release: None

Thu 01 Jun 2017 10:00:20 AM UTC, original submission:

Attached are two config files. One of them produces a crash (null pointer dereference) when fed to grub-syslinux2cfg or GRUB's syslinux_configfile command; the other produces an unhelpful 'kernel without label' message, without even so much as a line number. Both are understood by vanilla SYSLINUX normally; they are variously processed versons of SYSLINUX config file from SystemRescueCd.

The former bug is because the command-line arguments to ifcpu64.c32 are misparsed (GRUB's parser doesn't understand command-line arguments for kernel alternatives); the latter is because cmd_menudefault doesn't understand a label specifier in a MENU DEFAULT statement.

The SYSLINUX config parsing code generally seems quite fragile. From a very cursory inspection, I've noticed a potential memory leak when encountering multiple DEFAULT statements (cmd_default). A more thorough audit may reveal more such issues.

felix <felix_s>

 

Attached Files
file #40831:  crash.syslinux.cfg added by felix_s (6KiB - application/octet-stream)
file #40832:  syslinux.cfg added by felix_s (20KiB - application/octet-stream)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by felix_s (Submitted the item)
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    Follow 2 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 01 Jun 2017 10:00:20 AM UTCfelix_sAttached File-=>Added crash.syslinux.cfg, #40831
      Attached File-=>Added syslinux.cfg, #40832

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