| Message ID | 20200623123403.31676-2-dxld@darkboxed.org |
|---|---|
| State | Changes Requested |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [libnf_ct,resend,1/8] Handle negative snprintf return values properly | expand |
On Tue, Jun 23, 2020 at 02:33:56PM +0200, Daniel Gröber wrote: > Currently the BUFFER_SIZE macro doesn't take negative 'ret' values into > account. A negative return should just be passed through to the caller, > snprintf will already have set 'errno' properly. > > Signed-off-by: Daniel Gröber <dxld@darkboxed.org> > --- > include/internal/internal.h | 2 ++ > src/conntrack/api.c | 6 +++--- > src/conntrack/snprintf.c | 3 +++ > src/expect/snprintf.c | 3 +++ > 4 files changed, 11 insertions(+), 3 deletions(-) > > diff --git a/include/internal/internal.h b/include/internal/internal.h > index bb44e12..859724b 100644 > --- a/include/internal/internal.h > +++ b/include/internal/internal.h > @@ -41,6 +41,8 @@ > #endif > > #define BUFFER_SIZE(ret, size, len, offset) \ > + if(ret < 0) \ if (ret < 0) ^ missing space > + return -1; \ > size += ret; \ > if (ret > len) \ > ret = len; \ > diff --git a/src/conntrack/api.c b/src/conntrack/api.c > index ffa5216..78d7d61 100644 > --- a/src/conntrack/api.c > +++ b/src/conntrack/api.c > @@ -1099,9 +1099,9 @@ int nfct_catch(struct nfct_handle *h) > * print the message just after you receive the destroy event. If you want > * more accurate timestamping, use NFCT_OF_TIMESTAMP. > * > - * This function returns the size of the information that _would_ have been > - * written to the buffer, even if there was no room for it. Thus, the > - * behaviour is similar to snprintf. > + * On error, -1 is returned and errno is set appropiately. Otherwise the > + * size of what _would_ be written is returned, even if the size of the > + * buffer is insufficient. This behaviour is similar to snprintf. > */ > int nfct_snprintf(char *buf, > unsigned int size, > diff --git a/src/conntrack/snprintf.c b/src/conntrack/snprintf.c > index 17ad885..a87c0c9 100644 > --- a/src/conntrack/snprintf.c > +++ b/src/conntrack/snprintf.c > @@ -85,6 +85,9 @@ int __snprintf_conntrack(char *buf, > return -1; > } > > + if(size < 0) ^^^^^^^^ I can see spaces here as indentations. > + return size; > + > /* NULL terminated string */ > buf[size+1 > len ? len-1 : size] = '\0'; > > diff --git a/src/expect/snprintf.c b/src/expect/snprintf.c > index 3a104b5..b28ac62 100644 > --- a/src/expect/snprintf.c > +++ b/src/expect/snprintf.c > @@ -30,6 +30,9 @@ int __snprintf_expect(char *buf, > return -1; > } > > + if(size < 0) > + return size; > + > /* NULL terminated string */ > buf[size+1 > len ? len-1 : size] = '\0'; > > -- > 2.20.1 >
diff --git a/include/internal/internal.h b/include/internal/internal.h index bb44e12..859724b 100644 --- a/include/internal/internal.h +++ b/include/internal/internal.h @@ -41,6 +41,8 @@ #endif #define BUFFER_SIZE(ret, size, len, offset) \ + if(ret < 0) \ + return -1; \ size += ret; \ if (ret > len) \ ret = len; \ diff --git a/src/conntrack/api.c b/src/conntrack/api.c index ffa5216..78d7d61 100644 --- a/src/conntrack/api.c +++ b/src/conntrack/api.c @@ -1099,9 +1099,9 @@ int nfct_catch(struct nfct_handle *h) * print the message just after you receive the destroy event. If you want * more accurate timestamping, use NFCT_OF_TIMESTAMP. * - * This function returns the size of the information that _would_ have been - * written to the buffer, even if there was no room for it. Thus, the - * behaviour is similar to snprintf. + * On error, -1 is returned and errno is set appropiately. Otherwise the + * size of what _would_ be written is returned, even if the size of the + * buffer is insufficient. This behaviour is similar to snprintf. */ int nfct_snprintf(char *buf, unsigned int size, diff --git a/src/conntrack/snprintf.c b/src/conntrack/snprintf.c index 17ad885..a87c0c9 100644 --- a/src/conntrack/snprintf.c +++ b/src/conntrack/snprintf.c @@ -85,6 +85,9 @@ int __snprintf_conntrack(char *buf, return -1; } + if(size < 0) + return size; + /* NULL terminated string */ buf[size+1 > len ? len-1 : size] = '\0'; diff --git a/src/expect/snprintf.c b/src/expect/snprintf.c index 3a104b5..b28ac62 100644 --- a/src/expect/snprintf.c +++ b/src/expect/snprintf.c @@ -30,6 +30,9 @@ int __snprintf_expect(char *buf, return -1; } + if(size < 0) + return size; + /* NULL terminated string */ buf[size+1 > len ? len-1 : size] = '\0';
Currently the BUFFER_SIZE macro doesn't take negative 'ret' values into account. A negative return should just be passed through to the caller, snprintf will already have set 'errno' properly. Signed-off-by: Daniel Gröber <dxld@darkboxed.org> --- include/internal/internal.h | 2 ++ src/conntrack/api.c | 6 +++--- src/conntrack/snprintf.c | 3 +++ src/expect/snprintf.c | 3 +++ 4 files changed, 11 insertions(+), 3 deletions(-)