[debbugs-tracker] bug#22489: closed (A bug in tail.c)

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Your message dated Fri, 29 Jan 2016 10:29:57 -0800
with message-id <address@hidden>
and subject line Re: bug#22489: A bug in tail.c
has caused the debbugs.gnu.org bug report #22489,
regarding A bug in tail.c
to be marked as done.

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22489: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=22489
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--- Begin Message --- Subject: A bug in tail.c Date: Fri, 29 Jan 2016 20:38:39 +0800

Version: GNU Coreutils 8.20-8.25 ​

File: tail.c

Bug description: 

Line 1979,  parse_obsolete_option() function  has three parameters: argc, argv, n_units.  We only need to focus on argc and argv, which is from the main() function. Line 1992  filter  the argc and argv. When argc==2,  line 1998 p = argv[1], line 2000 *p++, then *p=argv[1][1], line 2026 while (ISDIGIT (*p)) access p. There is one condition can lead to program overflow, thus argc==2 and argv[1] has only one character, for example ./tail x , will access the next character after x, this maybe a bug, but can not lead program crash.

--WangLei

--- End Message ---

> --- Begin Message ---
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> Subject: 
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> Re: bug#22489: A bug in tail.c
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> Date: 
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> Fri, 29 Jan 2016 10:29:57 -0800
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> User-agent: 
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> Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0
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> On 01/29/2016 04:38 AM, Lei Wang wrote:
> > There is one condition can lead to program
> > overflow, thus argc==2 and argv[1] has only one character, for example
> > ./tail x , will access the next character after x, this maybe a bug
>
> I don't see a bug there. The next character is a null byte, and ISDIGIT 
> ('\0') is false so the code should do the right thing. I don't think 
> there is a test case that illustrates wrong behavior, but if I'm wrong 
> please reply with a test case (a shell command invoking 'tail') and I'll 
> reopen the bug report.
>
>
> --- End Message ---