Hi David, On 26 March 2018 at 07:25, David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote: > fdt_string() is used to retrieve strings from a DT blob's strings section. > It's rarely used directly, but is widely used internally. > > However, it doesn't do any bounds checking, which means in the case of a > corrupted blob it could access bad memory, which libfdt is supposed to > avoid. > > This write a safe alternative to fdt_string, fdt_get_string(). It checks > both that the given offset is within the string section and that the string > it points to is properly \0 terminated within the section. It also returns > the string's length as a convenience (since it needs to determine to do the > checks anyway). > > fdt_string() is rewritten in terms of fdt_get_string() for compatibility. > > Most of the diff here is actually testing infrastructure. > > Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> > --- > libfdt/fdt_ro.c | 61 +++++++++++++++++++++++++++++++++++-- > libfdt/libfdt.h | 18 ++++++++++- > libfdt/version.lds | 2 +- > tests/.gitignore | 1 + > tests/Makefile.tests | 2 +- > tests/run_tests.sh | 1 + > tests/testdata.h | 1 + > tests/testutils.c | 11 +++++-- > tests/trees.S | 26 ++++++++++++++++ > tests/truncated_string.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++ > 10 files changed, 193 insertions(+), 9 deletions(-) > create mode 100644 tests/truncated_string.c Similar code-size quesiton here. It looks like a lot of checking code. Can we have an option to remove it? > > diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c > index 4f4ef44..347aa7b 100644 > --- a/libfdt/fdt_ro.c > +++ b/libfdt/fdt_ro.c > @@ -76,17 +76,72 @@ static int fdt_nodename_eq_(const void *fdt, int offset, > return 0; > } > > +const char *fdt_get_string(const void *fdt, int stroffset, int *lenp) Comment? The difference between fdt_get_string() and fdt_string() is not obvious from the name. Regards, Simon -- To unsubscribe from this list: send the line "unsubscribe devicetree-compiler" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
