On Wed, Aug 30, 2023 at 09:07:24PM +0000, Azeem Shaikh 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 strscpy(). > > Direct replacement is safe here since return value of -errno > is used to check for truncation instead of sizeof(dest). > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > [2] https://github.com/KSPP/linux/issues/89 > > Signed-off-by: Azeem Shaikh <azeemshaikh38@xxxxxxxxx> > --- > v2: > * Replace all instances of strlcpy in this file instead of just 1. > > v1: > * https://lore.kernel.org/all/20230830200717.4129442-1-azeemshaikh38@xxxxxxxxx/ > > drivers/target/target_core_configfs.c | 27 ++++++++++++--------------- > 1 file changed, 12 insertions(+), 15 deletions(-) > > diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c > index 936e5ff1b209..10a22a428267 100644 > --- a/drivers/target/target_core_configfs.c > +++ b/drivers/target/target_core_configfs.c > @@ -1392,16 +1392,15 @@ static ssize_t target_wwn_vendor_id_store(struct config_item *item, > /* +2 to allow for a trailing (stripped) '\n' and null-terminator */ > unsigned char buf[INQUIRY_VENDOR_LEN + 2]; > char *stripped = NULL; > - size_t len; > + ssize_t len; > ssize_t ret; > > - len = strlcpy(buf, page, sizeof(buf)); > - if (len < sizeof(buf)) { > + len = strscpy(buf, page, sizeof(buf)); > + if (len > 0) { > /* Strip any newline added from userspace. */ > stripped = strstrip(buf); > - len = strlen(stripped); > } > - if (len > INQUIRY_VENDOR_LEN) { > + if (len < 0 || strlen(stripped) > INQUIRY_VENDOR_LEN) { > pr_err("Emulated T10 Vendor Identification exceeds" > " INQUIRY_VENDOR_LEN: " __stringify(INQUIRY_VENDOR_LEN) > "\n"); I would find these more readable if the "len = strlen" were left and the final "if" becomes: if (len < 0 || len > INQUIRY_VENDOR_LEN) > @@ -1448,16 +1447,15 @@ static ssize_t target_wwn_product_id_store(struct config_item *item, > /* +2 to allow for a trailing (stripped) '\n' and null-terminator */ > unsigned char buf[INQUIRY_MODEL_LEN + 2]; > char *stripped = NULL; > - size_t len; > + ssize_t len; > ssize_t ret; > > - len = strlcpy(buf, page, sizeof(buf)); > - if (len < sizeof(buf)) { > + len = strscpy(buf, page, sizeof(buf)); > + if (len > 0) { > /* Strip any newline added from userspace. */ > stripped = strstrip(buf); > - len = strlen(stripped); > } > - if (len > INQUIRY_MODEL_LEN) { > + if (len < 0 || strlen(stripped) > INQUIRY_MODEL_LEN) { > pr_err("Emulated T10 Vendor exceeds INQUIRY_MODEL_LEN: " > __stringify(INQUIRY_MODEL_LEN) > "\n"); > @@ -1504,16 +1502,15 @@ static ssize_t target_wwn_revision_store(struct config_item *item, > /* +2 to allow for a trailing (stripped) '\n' and null-terminator */ > unsigned char buf[INQUIRY_REVISION_LEN + 2]; > char *stripped = NULL; > - size_t len; > + ssize_t len; > ssize_t ret; > > - len = strlcpy(buf, page, sizeof(buf)); > - if (len < sizeof(buf)) { > + len = strscpy(buf, page, sizeof(buf)); > + if (len > 0) { > /* Strip any newline added from userspace. */ > stripped = strstrip(buf); > - len = strlen(stripped); > } > - if (len > INQUIRY_REVISION_LEN) { > + if (len < 0 || strlen(stripped) > INQUIRY_REVISION_LEN) { > pr_err("Emulated T10 Revision exceeds INQUIRY_REVISION_LEN: " > __stringify(INQUIRY_REVISION_LEN) > "\n"); > -- > 2.42.0.283.g2d96d420d3-goog > > -- Kees Cook
