| Message ID | 20230614001246.538643-1-azeemshaikh38@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] SUNRPC: Remove strlcpy | expand |
On June 13, 2023 5:12:46 PM PDT, Azeem Shaikh <azeemshaikh38@gmail.com> wrote: >strlcpy() reads the entire source buffer first. >This read may exceed the destination size limit. >This is both inefficient and can lead to linear read >overflows if a source string is not NUL-terminated [1]. >In an effort to remove strlcpy() completely [2], replace >strlcpy() here with sysfs_emit(). > >Direct replacement is safe here since the getter in kernel_params_ops >handles -errno return [3]. > >[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy >[2] https://github.com/KSPP/linux/issues/89 >[3] https://elixir.bootlin.com/linux/v6.4-rc6/source/include/linux/moduleparam.h#L52 > >Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com> >--- > net/sunrpc/svc.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > >diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c >index e6d4cec61e47..77326f163801 100644 >--- a/net/sunrpc/svc.c >+++ b/net/sunrpc/svc.c >@@ -109,13 +109,13 @@ param_get_pool_mode(char *buf, const struct kernel_param *kp) > switch (*ip) > { > case SVC_POOL_AUTO: >- return strlcpy(buf, "auto\n", 20); >+ return sysfs_emit(buf, "auto\n"); > case SVC_POOL_GLOBAL: >- return strlcpy(buf, "global\n", 20); >+ return sysfs_emit(buf, "global\n"); > case SVC_POOL_PERCPU: >- return strlcpy(buf, "percpu\n", 20); >+ return sysfs_emit(buf, "percpu\n"); > case SVC_POOL_PERNODE: >- return strlcpy(buf, "pernode\n", 20); >+ return sysfs_emit(buf, "pernode\n"); > default: > return sprintf(buf, "%d\n", *ip); Please replace the sprintf too (and then the Subject could be "use sysfs_emit" or so). -Kees
On Tue, Jun 13, 2023 at 9:04 PM Kees Cook <kees@kernel.org> wrote: > > On June 13, 2023 5:12:46 PM PDT, Azeem Shaikh <azeemshaikh38@gmail.com> wrote: > >strlcpy() reads the entire source buffer first. > >This read may exceed the destination size limit. > >This is both inefficient and can lead to linear read > >overflows if a source string is not NUL-terminated [1]. > >In an effort to remove strlcpy() completely [2], replace > >strlcpy() here with sysfs_emit(). > > > >Direct replacement is safe here since the getter in kernel_params_ops > >handles -errno return [3]. > > > >[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > >[2] https://github.com/KSPP/linux/issues/89 > >[3] https://elixir.bootlin.com/linux/v6.4-rc6/source/include/linux/moduleparam.h#L52 > > > >Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com> > >--- > > net/sunrpc/svc.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > >diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > >index e6d4cec61e47..77326f163801 100644 > >--- a/net/sunrpc/svc.c > >+++ b/net/sunrpc/svc.c > >@@ -109,13 +109,13 @@ param_get_pool_mode(char *buf, const struct kernel_param *kp) > > switch (*ip) > > { > > case SVC_POOL_AUTO: > >- return strlcpy(buf, "auto\n", 20); > >+ return sysfs_emit(buf, "auto\n"); > > case SVC_POOL_GLOBAL: > >- return strlcpy(buf, "global\n", 20); > >+ return sysfs_emit(buf, "global\n"); > > case SVC_POOL_PERCPU: > >- return strlcpy(buf, "percpu\n", 20); > >+ return sysfs_emit(buf, "percpu\n"); > > case SVC_POOL_PERNODE: > >- return strlcpy(buf, "pernode\n", 20); > >+ return sysfs_emit(buf, "pernode\n"); > > default: > > return sprintf(buf, "%d\n", *ip); > > Please replace the sprintf too (and then the Subject could be "use sysfs_emit" or so). Ah sorry, I missed the "replace default sprintf too" part in the previous thread. Resending. > > -Kees > > > > -- > Kees Cook
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index e6d4cec61e47..77326f163801 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -109,13 +109,13 @@ param_get_pool_mode(char *buf, const struct kernel_param *kp) switch (*ip) { case SVC_POOL_AUTO: - return strlcpy(buf, "auto\n", 20); + return sysfs_emit(buf, "auto\n"); case SVC_POOL_GLOBAL: - return strlcpy(buf, "global\n", 20); + return sysfs_emit(buf, "global\n"); case SVC_POOL_PERCPU: - return strlcpy(buf, "percpu\n", 20); + return sysfs_emit(buf, "percpu\n"); case SVC_POOL_PERNODE: - return strlcpy(buf, "pernode\n", 20); + return sysfs_emit(buf, "pernode\n"); default: return sprintf(buf, "%d\n", *ip); }
strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated [1]. In an effort to remove strlcpy() completely [2], replace strlcpy() here with sysfs_emit(). Direct replacement is safe here since the getter in kernel_params_ops handles -errno return [3]. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [2] https://github.com/KSPP/linux/issues/89 [3] https://elixir.bootlin.com/linux/v6.4-rc6/source/include/linux/moduleparam.h#L52 Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com> --- net/sunrpc/svc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)