On Tue, Sep 13, 2016 at 10:30 AM, Kevin Wolf <[email protected]> wrote: > Am 13.09.2016 um 11:15 hat Stefan Hajnoczi geschrieben: >> Section "7.1.4 Use of library functions" in the C99 standard says: >> >> If an argument to a function has an invalid value (such as [...] >> a null pointer [...]) [...] the behavior is undefined. >> >> Additionally the "searching and sorting" functions are specified as >> requiring valid pointer values as described in 7.1.4. >> >> This patch fixes the following static analyzer errors: > > "sanitizer", not "static analyzer" > >> block/qcow2.c:1807:41: runtime error: null pointer passed as argument 2, >> which is declared to never be null >> block/qcow2-cluster.c:86:26: runtime error: null pointer passed as >> argument 2, which is declared to never be null >> >> Reported-by: Peter Maydell <[email protected]> >> Signed-off-by: Stefan Hajnoczi <[email protected]> >> --- >> block/qcow2-cluster.c | 4 +++- >> block/qcow2.c | 5 ++++- >> 2 files changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c >> index f941835..ab0dcdc 100644 >> --- a/block/qcow2-cluster.c >> +++ b/block/qcow2-cluster.c >> @@ -83,7 +83,9 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t >> min_size, >> } >> memset(new_l1_table, 0, align_offset(new_l1_size2, 512)); >> >> - memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); >> + if (s->l1_table) { >> + memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); >> + } > > We could add 'else assert(s->l1_size == 0)' to make the intentions > clearer. Or actually, maybe the simpler way would be to do > 'if (s->l1_size)', then it's obvious that the skipped memcpy() wouldn't > do anything anyway. > >> /* write new table (align to cluster) */ >> BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE); >> diff --git a/block/qcow2.c b/block/qcow2.c >> index c079aa8..758a997 100644 >> --- a/block/qcow2.c >> +++ b/block/qcow2.c >> @@ -1804,7 +1804,10 @@ static size_t header_ext_add(char *buf, uint32_t >> magic, const void *s, >> .magic = cpu_to_be32(magic), >> .len = cpu_to_be32(len), >> }; >> - memcpy(buf + sizeof(QCowExtension), s, len); >> + >> + if (s) { >> + memcpy(buf + sizeof(QCowExtension), s, len); >> + } > > Same thing here. > > With or without the change: > > Reviewed-by: Kevin Wolf <[email protected]>
Thanks, I've made your suggested changes.
