From 6b9d4311d284debb0dba1d32757c965150d0d1d1 Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <ossi@users.sf.net>
Date: Thu, 25 Nov 2021 13:40:09 +0100
Subject: [PATCH] make IMAP parsing case insensitive

it's easy to overlook, but the spec demands this. we got away with it so
far, as everyone just uses UPPERCASE ... for the things we use so far.
---
 src/common.h   |  2 ++
 src/drv_imap.c | 19 +++++++++++++------
 src/util.c     |  7 +++++++
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/common.h b/src/common.h
index 4b43136..9a25b56 100644
--- a/src/common.h
+++ b/src/common.h
@@ -189,6 +189,8 @@ void *memrchr( const void *s, int c, size_t n );
 size_t strnlen( const char *str, size_t maxlen );
 #endif
 
+void to_upper( char *str, uint len );
+
 int starts_with( const char *str, int strl, const char *cmp, uint cmpl );
 int starts_with_upper( const char *str, int strl, const char *cmp, uint cmpl );
 int equals( const char *str, int strl, const char *cmp, uint cmpl );
diff --git a/src/drv_imap.c b/src/drv_imap.c
index a8c4fd6..b44df29 100644
--- a/src/drv_imap.c
+++ b/src/drv_imap.c
@@ -924,7 +924,7 @@ parse_imap_list( imap_store_t *ctx, char **sp, parse_list_state_t *sts )
 				if (sts->level && *s == ')')
 					break;
 			cur->len = (uint)(s - p);
-			if (equals( p, (int)cur->len, "NIL", 3 ))
+			if (equals_upper( p, (int)cur->len, "NIL", 3 ))
 				cur->val = NIL;
 			else
 				cur->val = nfstrndup( p, cur->len );
@@ -1086,12 +1086,13 @@ parse_fetched_flags( list_t *list, uchar *flags, uchar *status )
 		}
 		if (list->val[0] != '\\' && list->val[0] != '$')
 			continue;
-		if (equals( list->val, list->len, "\\Recent", 7 )) {
+		to_upper( list->val, list->len );
+		if (equals( list->val, list->len, "\\RECENT", 7 )) {
 			*status |= M_RECENT;
 			goto flagok;
 		}
 		for (uint i = 0; i < as(Flags); i++) {
-			if (!strcmp( Flags[i], list->val )) {
+			if (!strcasecmp( Flags[i], list->val )) {
 				*flags |= 1 << i;
 				goto flagok;
 			}
@@ -1169,9 +1170,10 @@ parse_fetch_rsp( imap_store_t *ctx, list_t *list )
 			error( "IMAP error: bogus item name in FETCH response\n" );
 			return LIST_BAD;
 		}
-		const char *name = tmp->val;
+		char *name = tmp->val;
 		uint namel = tmp->len;
 		tmp = tmp->next;
+		to_upper( name, namel );
 		if (equals( name, namel, "UID", 3 )) {
 			if (!is_atom( tmp ) || (uid = strtoul( tmp->val, &ep, 10 ), *ep)) {
 				error( "IMAP error: unable to parse UID\n" );
@@ -1282,6 +1284,7 @@ parse_capability( imap_store_t *ctx, char *cmd )
 	ctx->auth_mechs = NULL;
 	ctx->caps = 0x80000000;
 	while ((arg = next_arg( &cmd, &argl ))) {
+		to_upper( arg, argl );
 		if (starts_with( arg, argl, "AUTH=", 5 )) {
 			add_string_list_n( &ctx->auth_mechs, arg + 5, argl - 5 );
 		} else {
@@ -1308,6 +1311,7 @@ parse_response_code( imap_store_t *ctx, imap_cmd_t *cmd, char *s )
 		error( "IMAP error: malformed response code\n" );
 		return RESP_CANCEL;
 	}
+	to_upper( arg, argl );
 	if (equals( arg, argl, "UIDVALIDITY", 11 )) {
 		if (!(arg = next_arg( &s, &argl )) ||
 		    (ctx->uidvalidity = strtoul( arg, &earg, 10 ), *earg != ']'))
@@ -1374,7 +1378,7 @@ parse_response_code( imap_store_t *ctx, imap_cmd_t *cmd, char *s )
 				ret = RESP_CANCEL;
 				break;
 			}
-			if (equals( tmp->val, tmp->len, "\\*", 2 ) || equals( tmp->val, tmp->len, "$Forwarded", 10 )) {
+			if (equals( tmp->val, tmp->len, "\\*", 2 ) || equals_upper( tmp->val, tmp->len, "$FORWARDED", 10 )) {
 				ctx->has_forwarded = 1;
 				break;
 			}
@@ -1621,6 +1625,7 @@ imap_socket_read( void *aux )
 				break;
 			}
 
+			to_upper( arg, argl );
 			if (ctx->greeting == GreetingPending && equals( arg, argl, "PREAUTH", 7 )) {
 				parse_response_code( ctx, NULL, cmd );
 				ctx->greeting = GreetingPreauth;
@@ -1661,6 +1666,7 @@ imap_socket_read( void *aux )
 				resp = parse_list( ctx, cmd, parse_namespace_rsp, "NAMESPACE" );
 				goto listret;
 			} else if ((arg1 = next_arg( &cmd, &argl1 ))) {
+				to_upper( arg1, argl1 );
 				if (equals( arg1, argl1, "EXISTS", 6 )) {
 					ctx->total_msgs = atoi( arg );
 				} else if (equals( arg1, argl1, "EXPUNGE", 7 )) {
@@ -1736,13 +1742,14 @@ imap_socket_read( void *aux )
 				error( "IMAP error: malformed tagged response\n" );
 				break;
 			}
+			to_upper( arg, argl );
 			if (equals( arg, argl, "OK", 2 )) {
 				if (cmdp->param.to_trash)
 					ctx->trashnc = TrashKnown; /* Can't get NO [TRYCREATE] any more. */
 				resp = RESP_OK;
 			} else {
 				if (equals( arg, argl, "NO", 2 )) {
-					if (cmdp->param.create && cmd && starts_with( cmd, -1, "[TRYCREATE]", 11 )) { /* APPEND or UID COPY */
+					if (cmdp->param.create && cmd && starts_with_upper( cmd, -1, "[TRYCREATE]", 11 )) { /* APPEND or UID COPY */
 						imap_cmd_trycreate_t *cmd2 =
 							(imap_cmd_trycreate_t *)new_imap_cmd( sizeof(*cmd2) );
 						cmd2->orig_cmd = cmdp;
diff --git a/src/util.c b/src/util.c
index 162eb2a..c020399 100644
--- a/src/util.c
+++ b/src/util.c
@@ -284,6 +284,13 @@ strnlen( const char *str, size_t maxlen )
 
 #endif
 
+void
+to_upper( char *str, uint len )
+{
+	for (uint i = 0; i < len; i++)
+		str[i] = toupper( str[i] );
+}
+
 int
 starts_with( const char *str, int strl, const char *cmp, uint cmpl )
 {