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< Erlang patches mailing list ~ [PATCH] Truncate debug messages

Guest

Posted: Mon Apr 12, 2010 1:24 am

Guest

When the undocumented ERL_INET_GETHOST_DEBUG environment variable
is set to 5, very long hostnames can overflow the buffer used to
construct the debug message. Truncate the domain name to 255 bytes
(DOMAINNAME_MAX-3).

export ERL_INET_GETHOST_DEBUG=5
inet:gethostbyname(lists:duplicate(5000,"x")).
---
erts/etc/common/inet_gethost.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/erts/etc/common/inet_gethost.c b/erts/etc/common/inet_gethost.c
index ff16ee0..17f83e2 100644
--- a/erts/etc/common/inet_gethost.c
+++ b/erts/etc/common/inet_gethost.c
@@ -1746,7 +1746,7 @@ static int worker_loop(void)
}
proto = get_proto(req);
data = get_data(req);
- DEBUGF(4,("Worker got request, op = %d, proto = %d, data = %s.",
+ DEBUGF(4,("Worker got request, op = %d, proto = %d, data = %.255s.",
op,proto,data));
/* Got a request, lets go... */
switch (op) {
@@ -1762,14 +1762,14 @@ static int worker_loop(void)
hints.ai_flags = (AI_CANONNAME|AI_V4MAPPED|AI_ADDRCONFIG);
hints.ai_socktype = SOCK_STREAM;
hints.ai_family = AF_INET6;
- DEBUGF(5, ("Starting getaddrinfo(%s, ...)", data));
+ DEBUGF(5, ("Starting getaddrinfo(%.255s, ...)", data));
error_num = getaddrinfo((char *)data, NULL, &hints, &ai);
DEBUGF(5,("getaddrinfo returned %d", error_num));
if (error_num) {
error_num = map_netdb_error_ai(error_num);
}
#elif defined(HAVE_GETIPNODEBYNAME) /*#ifdef HAVE_GETADDRINFO */
- DEBUGF(5,("Starting getipnodebyname(%s)",data));
+ DEBUGF(5,("Starting getipnodebyname(%.255s)",data));
he = getipnodebyname(data, AF_INET6, AI_DEFAULT, &error_num);
if (he) {
free_he = 1;
@@ -1780,7 +1780,7 @@ static int worker_loop(void)
error_num = map_netdb_error(error_num);
}
#elif defined(HAVE_GETHOSTBYNAME2) /*#ifdef HAVE_GETADDRINFO */
- DEBUGF(5,("Starting gethostbyname2(%s, AF_INET6)",data));
+ DEBUGF(5,("Starting gethostbyname2(%.255s, AF_INET6)",data));
he = gethostbyname2((char*)data, AF_INET6);
if (he) {
error_num = 0;
@@ -1796,7 +1796,7 @@ static int worker_loop(void)
#endif /*ifdef HAVE_IN6 */

case PROTO_IPV4: { /* switch (proto) { */
- DEBUGF(5,("Starting gethostbyname(%s)",data));
+ DEBUGF(5,("Starting gethostbyname(%.255s)",data));
he = gethostbyname((char*)data);
if (he) {
error_num = 0;
--
1.5.6.4

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Guest

Posted: Mon Apr 12, 2010 1:24 am

Guest

Posted: Mon Apr 12, 2010 9:47 am

Guest

Michael Santos writes:
> When the undocumented ERL_INET_GETHOST_DEBUG environment variable
> is set to 5, very long hostnames can overflow the buffer used to
> construct the debug message. Truncate the domain name to 255 bytes
> (DOMAINNAME_MAX-3).
>
> export ERL_INET_GETHOST_DEBUG=5
> inet:gethostbyname(lists:duplicate(5000,"x")).
> ---
> erts/etc/common/inet_gethost.c | 10 +++++-----
> 1 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/erts/etc/common/inet_gethost.c b/erts/etc/common/inet_gethost.c
> index ff16ee0..17f83e2 100644
> --- a/erts/etc/common/inet_gethost.c
> +++ b/erts/etc/common/inet_gethost.c
> @@ -1746,7 +1746,7 @@ static int worker_loop(void)
> }
> proto = get_proto(req);
> data = get_data(req);
> - DEBUGF(4,("Worker got request, op = %d, proto = %d, data = %s.",
> + DEBUGF(4,("Worker got request, op = %d, proto = %d, data = %.255s.",

etc.

I believe the better solution is to replace the unsafe vsprintf()
calls in inet_gethost.c with erts_vsnprintf() calls.

________________________________________________________________
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Guest

Posted: Mon Apr 12, 2010 9:48 am

Guest

Posted: Tue Apr 13, 2010 12:22 am

Guest

When the undocumented ERL_INET_GETHOST_DEBUG environment variable
is set to 5, very long hostnames can overflow the buffer used to
construct the debug message. Truncate debug messages if they exceed
the size of the buffer.

export ERL_INET_GETHOST_DEBUG=5
inet:gethostbyname(lists:duplicate(5000,"x")).
---
erts/etc/common/Makefile.in | 10 +++++-----
erts/etc/common/inet_gethost.c | 8 +++++---
2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/erts/etc/common/Makefile.in b/erts/etc/common/Makefile.in
index 3db4fcb..d2a5080 100644
--- a/erts/etc/common/Makefile.in
+++ b/erts/etc/common/Makefile.in
@@ -96,9 +96,9 @@ endif

# On windows we always need reentrant libraries.
ifeq ($(TARGET),win32)
-ERLEXEC_XLIBS=-L../../lib/internal/$(TARGET) -lerts_internal_r$(ERTS_LIB_TYPEMARKER) @ERTS_INTERNAL_X_LIBS@
+ERTS_INTERNAL_LIBS=-L../../lib/internal/$(TARGET) -lerts_internal_r$(ERTS_LIB_TYPEMARKER) @ERTS_INTERNAL_X_LIBS@
else
-ERLEXEC_XLIBS=-L../../lib/internal/$(TARGET) -lerts_internal$(ERTS_LIB_TYPEMARKER) @ERTS_INTERNAL_X_LIBS@
+ERTS_INTERNAL_LIBS=-L../../lib/internal/$(TARGET) -lerts_internal$(ERTS_LIB_TYPEMARKER) @ERTS_INTERNAL_X_LIBS@
endif

# ----------------------------------------------------
@@ -295,7 +295,7 @@ $(OBJDIR)/inet_gethost.o: inet_gethost.c
$(CC) $(CFLAGS) -o $@ -c inet_gethost.c

$(BINDIR)/inet_gethost@EXEEXT@: $(OBJDIR)/inet_gethost.o $(ENTRY_OBJ)
- $(PURIFY) $(LD) $(LDFLAGS) $(ENTRY_LDFLAGS) -o $@ $(OBJDIR)/inet_gethost.o $(ENTRY_OBJ) $(LIBS)
+ $(PURIFY) $(LD) $(LDFLAGS) $(ENTRY_LDFLAGS) -o $@ $(OBJDIR)/inet_gethost.o $(ENTRY_OBJ) $(LIBS) $(ERTS_INTERNAL_LIBS)

$(BINDIR)/run_erl: $(OBJDIR)/safe_string.o $(OBJDIR)/run_erl.o
$(LD) $(LDFLAGS) -o $@ $(OBJDIR)/safe_string.o $(OBJDIR)/run_erl.o $(LIBS)
@@ -320,7 +320,7 @@ $(OBJDIR)/safe_string.o: ../unix/safe_string.c

ifneq ($(TARGET),win32)
$(BINDIR)/$(ERLEXEC): $(OBJDIR)/$(ERLEXEC).o
- $(PURIFY) $(LD) $(LDFLAGS) -o $@ $(OBJDIR)/$(ERLEXEC).o $(ERLEXEC_XLIBS)
+ $(PURIFY) $(LD) $(LDFLAGS) -o $@ $(OBJDIR)/$(ERLEXEC).o $(ERTS_INTERNAL_LIBS)

$(OBJDIR)/$(ERLEXEC).o: $(ERLEXECDIR)/$(ERLEXEC).c
$(CC) -I$(EMUDIR) $(CFLAGS) -o $@ -c $(ERLEXECDIR)/$(ERLEXEC).c
@@ -360,7 +360,7 @@ $(OBJDIR)/escript.o: escript.c
ifeq ($(TARGET),win32)

$(BINDIR)/$(ERLEXEC): $(OBJDIR)/erlexec.o $(OBJDIR)/win_erlexec.o $(OBJDIR)/init_file.o $(OBJDIR)/$(ERLRES_OBJ)
- $(LD) -dll $(LDFLAGS) -o $@ $(OBJDIR)/erlexec.o $(OBJDIR)/win_erlexec.o $(OBJDIR)/init_file.o $(OBJDIR)/$(ERLRES_OBJ) $(ERLEXEC_XLIBS)
+ $(LD) -dll $(LDFLAGS) -o $@ $(OBJDIR)/erlexec.o $(OBJDIR)/win_erlexec.o $(OBJDIR)/init_file.o $(OBJDIR)/$(ERLRES_OBJ) $(ERTS_INTERNAL_LIBS)

$(BINDIR)/erl@EXEEXT@: $(OBJDIR)/erl.o $(OBJDIR)/init_file.o $(OBJDIR)/$(ERLRES_OBJ)
$(LD) $(LDFLAGS) -o $@ $(OBJDIR)/erl.o $(OBJDIR)/init_file.o $(OBJDIR)/$(ERLRES_OBJ)
diff --git a/erts/etc/common/inet_gethost.c b/erts/etc/common/inet_gethost.c
index ff16ee0..bd2be47 100644
--- a/erts/etc/common/inet_gethost.c
+++ b/erts/etc/common/inet_gethost.c
@@ -52,6 +52,8 @@
# include "config.h"
#endif

+#include "erl_printf.h"
+
#ifdef WIN32

#define WIN32_LEAN_AND_MEAN
@@ -2552,7 +2554,7 @@ static void debugf(char *format, ...)
sprintf(buff,"%s[%d] (DEBUG):",program_name,(int) getpid());
#endif
ptr = buff + strlen(buff);
- vsprintf(ptr,format,ap);
+ erts_vsnprintf(ptr,sizeof(buff)-strlen(buff)-2,format,ap);
strcat(ptr,"\r\n");
#ifdef WIN32
if (debug_console_allocated != INVALID_HANDLE_VALUE) {
@@ -2574,7 +2576,7 @@ static void warning(char *format, ...)
va_start(ap,format);
sprintf(buff,"%s[%d]: WARNING:",program_name, (int) getpid());
ptr = buff + strlen(buff);
- vsprintf(ptr,format,ap);
+ erts_vsnprintf(ptr,sizeof(buff)-strlen(buff)-2,format,ap);
strcat(ptr,"\r\n");
#ifdef WIN32
{
@@ -2596,7 +2598,7 @@ static void fatal(char *format, ...)
va_start(ap,format);
sprintf(buff,"%s[%d]: FATAL ERROR:",program_name, (int) getpid());
ptr = buff + strlen(buff);
- vsprintf(ptr,format,ap);
+ erts_vsnprintf(ptr,sizeof(buff)-strlen(buff)-2,format,ap);
strcat(ptr,"\r\n");
#ifdef WIN32
{
--
1.5.6.4

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See http://www.erlang.org/faq.html
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Guest

Posted: Tue Apr 13, 2010 12:22 am

Guest

Posted: Tue Apr 13, 2010 5:40 am

Guest

On Tue, Apr 13, 2010 at 2:22 AM, Michael Santos
<michael.santos@gmail.com> wrote:
> When the undocumented ERL_INET_GETHOST_DEBUG environment variable
> is set to 5, very long hostnames can overflow the buffer used to
> construct the debug message. Truncate debug messages if they exceed
> the size of the buffer.

Thanks! Will include in 'pu'.

--
Björn Gustavsson, Erlang/OTP, Ericsson AB

________________________________________________________________
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See http://www.erlang.org/faq.html
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Guest

Posted: Tue Apr 13, 2010 5:40 am

Guest

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< Erlang patches mailing list ~ [PATCH] Truncate debug messages