| Message ID | 20211021140839.7439-1-cgzones@googlemail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | libsepol: avoid passing NULL pointer to memcpy | expand |
On Thu, Oct 21, 2021 at 10:09 AM Christian Göttsche <cgzones@googlemail.com> wrote: > > memcpy(3) might be annotated with the function attribute nonnull and > UBSan then complains: > > module.c:296:3: runtime error: null pointer passed as argument 2, which is declared to never be null > #0 0x7f2468efa5b3 in link_netfilter_contexts ./libsepol/src/module.c:296 > #1 0x7f2468efa5b3 in sepol_link_packages ./libsepol/src/module.c:337 > #2 0x562331e9e123 in main ./semodule-utils/semodule_link/semodule_link.c:145 > #3 0x7f2467e247ec in __libc_start_main ../csu/libc-start.c:332 > #4 0x562331e9d2a9 in _start (./destdir/usr/bin/semodule_link+0x32a9) > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com> > --- > libsepol/src/module.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/libsepol/src/module.c b/libsepol/src/module.c > index 02a5de2c..ed777f8e 100644 > --- a/libsepol/src/module.c > +++ b/libsepol/src/module.c > @@ -293,9 +293,11 @@ static int link_netfilter_contexts(sepol_module_package_t * base, > } > base->netfilter_contexts = base_context; > for (i = 0; i < num_modules; i++) { > - memcpy(base->netfilter_contexts + base->netfilter_contexts_len, > - modules[i]->netfilter_contexts, > - modules[i]->netfilter_contexts_len); > + if (modules[i]->netfilter_contexts_len > 0) { > + memcpy(base->netfilter_contexts + base->netfilter_contexts_len, > + modules[i]->netfilter_contexts, > + modules[i]->netfilter_contexts_len); > + } > base->netfilter_contexts_len += > modules[i]->netfilter_contexts_len; This line should be in the if statement as well. There is no point in adding a 0, since the check for > 0 is already being made. Jim > } > -- > 2.33.0 >
diff --git a/libsepol/src/module.c b/libsepol/src/module.c index 02a5de2c..ed777f8e 100644 --- a/libsepol/src/module.c +++ b/libsepol/src/module.c @@ -293,9 +293,11 @@ static int link_netfilter_contexts(sepol_module_package_t * base, } base->netfilter_contexts = base_context; for (i = 0; i < num_modules; i++) { - memcpy(base->netfilter_contexts + base->netfilter_contexts_len, - modules[i]->netfilter_contexts, - modules[i]->netfilter_contexts_len); + if (modules[i]->netfilter_contexts_len > 0) { + memcpy(base->netfilter_contexts + base->netfilter_contexts_len, + modules[i]->netfilter_contexts, + modules[i]->netfilter_contexts_len); + } base->netfilter_contexts_len += modules[i]->netfilter_contexts_len; }
memcpy(3) might be annotated with the function attribute nonnull and UBSan then complains: module.c:296:3: runtime error: null pointer passed as argument 2, which is declared to never be null #0 0x7f2468efa5b3 in link_netfilter_contexts ./libsepol/src/module.c:296 #1 0x7f2468efa5b3 in sepol_link_packages ./libsepol/src/module.c:337 #2 0x562331e9e123 in main ./semodule-utils/semodule_link/semodule_link.c:145 #3 0x7f2467e247ec in __libc_start_main ../csu/libc-start.c:332 #4 0x562331e9d2a9 in _start (./destdir/usr/bin/semodule_link+0x32a9) Signed-off-by: Christian Göttsche <cgzones@googlemail.com> --- libsepol/src/module.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)