Hi Arnd, On Tue, 1 Aug 2017 11:20:26 -0700 Kees Cook <[email protected]> wrote: > > On Tue, Aug 1, 2017 at 5:04 AM, Arnd Bergmann <[email protected]> wrote: > > After commit 62d1034f53e3 ("fortify: use WARN instead of BUG for now"), we > > get a warning in adfs about a possible buffer overflow: > > > > In function 'memcpy', > > inlined from '__adfs_dir_put' at fs/adfs/dir_f.c:318:2, > > inlined from 'adfs_f_update' at fs/adfs/dir_f.c:403:2: > > include/linux/string.h:305:4: error: call to '__read_overflow2' declared > > with attribute error: detected read beyond size of object passed as 2nd > > parameter > > __read_overflow2(); > > ^~~~~~~~~~~~~~~~~~ > > > > The warning is correct in the sense that a negative 'pos' argument > > to the function would have that result. However, this is not a bug, > > as we know the position is always positive (in fact, between 5 > > and 2007, inclusive) when the function gets called. > > > > Changing the variable to a unsigned type avoids the problem. I decided > > to use 'unsigned int' for the position in the directory and the block > > number, as they are both counting things, but use size_t for the > > offset and length that get passed into memcpy. This shuts up the > > warning. > > > > Signed-off-by: Arnd Bergmann <[email protected]> > > Acked-by: Kees Cook <[email protected]> > > Thanks for the fix! (Added sfr to Cc since he noticed this too.)
Can someone please send me the patch so I can use it if Andrew doesn't get around to updating mmotd today? -- Cheers, Stephen Rothwell
