Fix PKCS7_verify to not have an error stack if it succeeds.

Revert a change in behavior to BIO_write(). If a NULL BIO
is passed, no error is raised and the return value is 0. There are
many places where the return code from the write was not checked,
resulting in an error stack with no error status being returned.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15493)

1 files changed, 14 insertions, 12 deletions

diff --git a/doc/man3/BIO_read.pod b/doc/man3/BIO_read.pod
index 6a02a86b6c..d9201ef3b7 100644
--- a/doc/man3/BIO_read.pod
+++ b/doc/man3/BIO_read.pod
@@ -21,19 +21,19 @@ BIO_gets, BIO_get_line, BIO_puts
 
 =head1 DESCRIPTION
 
-BIO_read_ex() attempts to read B<dlen> bytes from BIO B<b> and places the data
-in B<data>. If any bytes were successfully read then the number of bytes read is
-stored in B<*readbytes>.
+BIO_read_ex() attempts to read I<dlen> bytes from BIO I<b> and places the data
+in I<data>. If any bytes were successfully read then the number of bytes read is
+stored in I<*readbytes>.
 
-BIO_write_ex() attempts to write B<dlen> bytes from B<data> to BIO B<b>. If
-successful then the number of bytes written is stored in B<*written>.
+BIO_write_ex() attempts to write I<dlen> bytes from I<data> to BIO I<b>. If
+successful then the number of bytes written is stored in I<*written>.
 
-BIO_read() attempts to read B<len> bytes from BIO B<b> and places
-the data in B<buf>.
+BIO_read() attempts to read I<len> bytes from BIO I<b> and places
+the data in I<buf>.
 
 BIO_gets() performs the BIOs "gets" operation and places the data
-in B<buf>. Usually this operation will attempt to read a line of data
-from the BIO of maximum length B<size-1>. There are exceptions to this,
+in I<buf>. Usually this operation will attempt to read a line of data
+from the BIO of maximum length I<size-1>. There are exceptions to this,
 however; for example, BIO_gets() on a digest BIO will calculate and
 return the digest and other BIOs may not support BIO_gets() at all.
 The returned string is always NUL-terminated and the '\n' is preserved
@@ -42,22 +42,24 @@ On binary input there may be NUL characters within the string;
 in this case the return value (if nonnegative) may give an incorrect length.
 
 BIO_get_line() attempts to read from BIO <b> a line of data up to the next '\n'
-or the maximum length B<size-1> is reached and places the data in B<buf>.
+or the maximum length I<size-1> is reached and places the data in I<buf>.
 The returned string is always NUL-terminated and the '\n' is preserved
 if present in the input data.
 On binary input there may be NUL characters within the string;
 in this case the return value (if nonnegative) gives the actual length read.
 For implementing this, unfortunately the data needs to be read byte-by-byte.
 
-BIO_write() attempts to write B<len> bytes from B<buf> to BIO B<b>.
+BIO_write() attempts to write I<len> bytes from I<buf> to BIO I<b>.
 
-BIO_puts() attempts to write a NUL-terminated string B<buf> to BIO B<b>.
+BIO_puts() attempts to write a NUL-terminated string I<buf> to BIO I<b>.
 
 =head1 RETURN VALUES
 
 BIO_read_ex() and BIO_write_ex() return 1 if data was successfully read or
 written, and 0 otherwise.
 
+BIO_write() and BIO_write_ex() return 0 if the BIO I<b> is NULL.
+
 BIO_gets() returns -2 if the "gets" operation is not implemented by the BIO
 or -1 on other errors.
 Otherwise it typically returns the amount of data read,