Hi,

On Fri, Nov 19, 2021 at 01:04:39AM +0300, Dmitry V. Levin wrote:
> On Thu, Nov 18, 2021 at 07:44:50PM +0000, Matthias Maennich via 
> Elfutils-devel wrote:
> > dwfl_linux_kernel_report_modules_ has an outstanding ancient bug when
> > reading kernel module information from a modules list file. The target
> > buffer for the module name was sized too small to hold potential values.
> > Fix that by increasing the value to account for the null termination.
> > 
> > In practice, this unlikely ever happened, but it now got diagnosed by
> > LLVM as part of a stricter -Wfortify-source implementation [1]:
> > 
> > libdwfl/linux-kernel-modules.c:1019:7: error: 'sscanf' may overflow; 
> > destination buffer in argument 3 has size 128, but the corresponding 
> > specifier may require size 129 [-Werror,-Wfortify-source]
> >                     modname, &modsz, &modaddr) == 3)
> > 
> > [1] 
> > https://github.com/llvm/llvm-project/commit/2db66f8d48beeea835cb9a6940e25bc04ab5d941
> > 
> > Suggested-by: Paul Pluzhnikov <ppluzhni...@google.com>
> > Signed-off-by: Matthias Maennich <maenn...@google.com>
> > Change-Id: I97b4fcb536273e5ccc4e37b0b9f0f8ffb7487909
> > ---
> >  libdwfl/linux-kernel-modules.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/libdwfl/linux-kernel-modules.c b/libdwfl/linux-kernel-modules.c
> > index c0f8dfa4aef2..58c0c417a597 100644
> > --- a/libdwfl/linux-kernel-modules.c
> > +++ b/libdwfl/linux-kernel-modules.c
> > @@ -1008,7 +1008,7 @@ dwfl_linux_kernel_report_modules (Dwfl *dwfl)
> >    int result = 0;
> >    Dwarf_Addr modaddr;
> >    unsigned long int modsz;
> > -  char modname[128];
> > +  char modname[128+1];
> >    char *line = NULL;
> >    size_t linesz = 0;
> >    /* We can't just use fscanf here because it's not easy to distinguish \n
> 
> LGTM, thanks.

Agreed. Added a ChangeLog entry and pushed.

Thanks,

Mark

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