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sftp: Reformat read/write functions

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Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
This commit is contained in:
Jakub Jelen
2025-01-13 13:50:48 +01:00
parent 00fce9cb6c
commit 4af88c84d4
1 changed files with 329 additions and 304 deletions
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633
src/sftp.c
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@@ -1131,365 +1131,390 @@ void sftp_file_set_blocking(sftp_file handle)
} }
/* Read from a file using an opened sftp file handle. */ /* Read from a file using an opened sftp file handle. */
ssize_t sftp_read(sftp_file handle, void *buf, size_t count) { ssize_t
sftp_session sftp; sftp_read(sftp_file handle, void *buf, size_t count)
sftp_message msg = NULL; {
sftp_status_message status; sftp_session sftp = NULL;
ssh_string datastring; sftp_message msg = NULL;
size_t datalen; sftp_status_message status;
ssh_buffer buffer; ssh_string datastring = NULL;
uint32_t id; size_t datalen;
int rc; ssh_buffer buffer = NULL;
uint32_t id;
int rc;
if (handle == NULL) { if (handle == NULL) {
return -1; return -1;
} }
sftp = handle->sftp; sftp = handle->sftp;
if (handle->eof) { if (handle->eof) {
return 0; return 0;
} }
/* /*
* limit the reads to the maximum specified in Section 3 of * limit the reads to the maximum specified in Section 3 of
* https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-02 * https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-02
* or to the values provided by the limits@openssh.com extension. * or to the values provided by the limits@openssh.com extension.
* *
* TODO: We should iterate over the blocks rather than writing less than * TODO: We should iterate over the blocks rather than writing less than
* requested to provide less surprises to the calling applications. * requested to provide less surprises to the calling applications.
*/ */
if (count > sftp->limits->max_read_length) { if (count > sftp->limits->max_read_length) {
if (sftp->limits->max_read_length > SIZE_MAX) { if (sftp->limits->max_read_length > SIZE_MAX) {
return SSH_ERROR; return SSH_ERROR;
} }
count = (size_t)sftp->limits->max_read_length; count = (size_t)sftp->limits->max_read_length;
} }
buffer = ssh_buffer_new(); buffer = ssh_buffer_new();
if (buffer == NULL) { if (buffer == NULL) {
ssh_set_error_oom(sftp->session); ssh_set_error_oom(sftp->session);
return -1; return -1;
} }
id = sftp_get_new_id(handle->sftp); id = sftp_get_new_id(handle->sftp);
rc = ssh_buffer_pack(buffer, rc = ssh_buffer_pack(buffer,
"dSqd", "dSqd",
id, id,
handle->handle, handle->handle,
handle->offset, handle->offset,
count); count);
if (rc != SSH_OK){ if (rc != SSH_OK) {
ssh_set_error_oom(sftp->session); ssh_set_error_oom(sftp->session);
SSH_BUFFER_FREE(buffer);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
if (sftp_packet_write(handle->sftp, SSH_FXP_READ, buffer) < 0) {
SSH_BUFFER_FREE(buffer);
return -1;
}
SSH_BUFFER_FREE(buffer); SSH_BUFFER_FREE(buffer);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
if (sftp_packet_write(handle->sftp, SSH_FXP_READ, buffer) < 0) {
SSH_BUFFER_FREE(buffer);
return -1;
}
SSH_BUFFER_FREE(buffer);
rc = sftp_recv_response_msg(handle->sftp, id, !handle->nonblocking, &msg); rc = sftp_recv_response_msg(handle->sftp, id, !handle->nonblocking, &msg);
if (rc == SSH_ERROR) { if (rc == SSH_ERROR) {
return -1; return -1;
} }
if (rc == SSH_AGAIN) { if (rc == SSH_AGAIN) {
/* /*
* file opened in non blocking mode and the response has not arrived yet. * file opened in non blocking mode and the response has not arrived
* Since we cannot block, return 0 as the number of bytes read. * yet. Since we cannot block, return 0 as the number of bytes read.
*/ */
return 0; return 0;
} }
switch (msg->packet_type) { switch (msg->packet_type) {
case SSH_FXP_STATUS: case SSH_FXP_STATUS:
status = parse_status_msg(msg); status = parse_status_msg(msg);
sftp_message_free(msg); sftp_message_free(msg);
if (status == NULL) { if (status == NULL) {
return -1; return -1;
} }
sftp_set_error(sftp, status->status); sftp_set_error(sftp, status->status);
switch (status->status) { switch (status->status) {
case SSH_FX_EOF: case SSH_FX_EOF:
handle->eof = 1; handle->eof = 1;
status_msg_free(status); status_msg_free(status);
return 0; return 0;
default: default:
break; break;
} }
ssh_set_error(sftp->session,SSH_REQUEST_DENIED, ssh_set_error(sftp->session,
"SFTP server: %s", status->errormsg); SSH_REQUEST_DENIED,
status_msg_free(status); "SFTP server: %s",
return -1; status->errormsg);
status_msg_free(status);
return -1;
case SSH_FXP_DATA: case SSH_FXP_DATA:
datastring = ssh_buffer_get_ssh_string(msg->payload); datastring = ssh_buffer_get_ssh_string(msg->payload);
sftp_message_free(msg); sftp_message_free(msg);
if (datastring == NULL) { if (datastring == NULL) {
ssh_set_error(sftp->session, SSH_FATAL, ssh_set_error(sftp->session,
"Received invalid DATA packet from sftp server"); SSH_FATAL,
return -1; "Received invalid DATA packet from sftp server");
} return -1;
}
datalen = ssh_string_len(datastring); datalen = ssh_string_len(datastring);
if (datalen > count) { if (datalen > count) {
ssh_set_error(sftp->session, SSH_FATAL, ssh_set_error(sftp->session,
"Received a too big DATA packet from sftp server: " SSH_FATAL,
"%zu and asked for %zu", "Received a too big DATA packet from sftp server: "
datalen, count); "%zu and asked for %zu",
datalen,
count);
SSH_STRING_FREE(datastring);
return -1;
}
handle->offset += (uint64_t)datalen;
memcpy(buf, ssh_string_data(datastring), datalen);
SSH_STRING_FREE(datastring); SSH_STRING_FREE(datastring);
return -1; return datalen;
}
handle->offset += (uint64_t)datalen;
memcpy(buf, ssh_string_data(datastring), datalen);
SSH_STRING_FREE(datastring);
return datalen;
default: default:
ssh_set_error(sftp->session, SSH_FATAL, ssh_set_error(sftp->session,
"Received message %d during read!", msg->packet_type); SSH_FATAL,
sftp_message_free(msg); "Received message %d during read!",
sftp_set_error(sftp, SSH_FX_BAD_MESSAGE); msg->packet_type);
return -1; sftp_message_free(msg);
} sftp_set_error(sftp, SSH_FX_BAD_MESSAGE);
return -1;
}
return -1; /* not reached */ return -1; /* not reached */
} }
/* Start an asynchronous read from a file using an opened sftp file handle. */ /* Start an asynchronous read from a file using an opened sftp file handle. */
int sftp_async_read_begin(sftp_file file, uint32_t len){ int
sftp_session sftp = file->sftp; sftp_async_read_begin(sftp_file file, uint32_t len)
ssh_buffer buffer; {
uint32_t id; sftp_session sftp = file->sftp;
int rc; ssh_buffer buffer = NULL;
uint32_t id;
int rc;
buffer = ssh_buffer_new(); buffer = ssh_buffer_new();
if (buffer == NULL) { if (buffer == NULL) {
ssh_set_error_oom(sftp->session); ssh_set_error_oom(sftp->session);
sftp_set_error(sftp, SSH_FX_FAILURE); sftp_set_error(sftp, SSH_FX_FAILURE);
return -1; return -1;
} }
id = sftp_get_new_id(sftp); id = sftp_get_new_id(sftp);
rc = ssh_buffer_pack(buffer, rc = ssh_buffer_pack(buffer, "dSqd", id, file->handle, file->offset, len);
"dSqd", if (rc != SSH_OK) {
id, ssh_set_error_oom(sftp->session);
file->handle, SSH_BUFFER_FREE(buffer);
file->offset, sftp_set_error(sftp, SSH_FX_FAILURE);
len); return -1;
if (rc != SSH_OK) { }
ssh_set_error_oom(sftp->session); if (sftp_packet_write(sftp, SSH_FXP_READ, buffer) < 0) {
SSH_BUFFER_FREE(buffer);
return -1;
}
SSH_BUFFER_FREE(buffer); SSH_BUFFER_FREE(buffer);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
if (sftp_packet_write(sftp, SSH_FXP_READ, buffer) < 0) {
SSH_BUFFER_FREE(buffer);
return -1;
}
SSH_BUFFER_FREE(buffer);
file->offset += len; /* assume we'll read len bytes */ file->offset += len; /* assume we'll read len bytes */
return id; return id;
} }
/* Wait for an asynchronous read to complete and save the data. */ /* Wait for an asynchronous read to complete and save the data. */
int sftp_async_read(sftp_file file, void *data, uint32_t size, uint32_t id){ int
sftp_session sftp; sftp_async_read(sftp_file file, void *data, uint32_t size, uint32_t id)
sftp_message msg = NULL; {
sftp_status_message status; sftp_session sftp = NULL;
ssh_string datastring; sftp_message msg = NULL;
int rc, err = SSH_OK; sftp_status_message status;
size_t len; ssh_string datastring = NULL;
int rc, err = SSH_OK;
size_t len;
if (file == NULL) { if (file == NULL) {
return SSH_ERROR; return SSH_ERROR;
} }
sftp = file->sftp; sftp = file->sftp;
if (file->eof) { if (file->eof) {
return 0; return 0;
} }
/* handle an existing request */ /* handle an existing request */
rc = sftp_recv_response_msg(sftp, id, !file->nonblocking, &msg); rc = sftp_recv_response_msg(sftp, id, !file->nonblocking, &msg);
if (rc == SSH_ERROR || rc == SSH_AGAIN) { if (rc == SSH_ERROR || rc == SSH_AGAIN) {
return rc; return rc;
} }
switch (msg->packet_type) { switch (msg->packet_type) {
case SSH_FXP_STATUS: case SSH_FXP_STATUS:
status = parse_status_msg(msg); status = parse_status_msg(msg);
sftp_message_free(msg); sftp_message_free(msg);
if (status == NULL) { if (status == NULL) {
return -1; return -1;
} }
sftp_set_error(sftp, status->status); sftp_set_error(sftp, status->status);
if (status->status != SSH_FX_EOF) { if (status->status != SSH_FX_EOF) {
ssh_set_error(sftp->session, SSH_REQUEST_DENIED, ssh_set_error(sftp->session,
"SFTP server : %s", status->errormsg); SSH_REQUEST_DENIED,
err = SSH_ERROR; "SFTP server : %s",
} else { status->errormsg);
file->eof = 1; err = SSH_ERROR;
} } else {
status_msg_free(status); file->eof = 1;
return err; }
status_msg_free(status);
return err;
case SSH_FXP_DATA: case SSH_FXP_DATA:
datastring = ssh_buffer_get_ssh_string(msg->payload); datastring = ssh_buffer_get_ssh_string(msg->payload);
sftp_message_free(msg); sftp_message_free(msg);
if (datastring == NULL) { if (datastring == NULL) {
ssh_set_error(sftp->session, SSH_FATAL, ssh_set_error(sftp->session,
"Received invalid DATA packet from sftp server"); SSH_FATAL,
return SSH_ERROR; "Received invalid DATA packet from sftp server");
} return SSH_ERROR;
if (ssh_string_len(datastring) > size) { }
ssh_set_error(sftp->session, SSH_FATAL, if (ssh_string_len(datastring) > size) {
"Received a too big DATA packet from sftp server: " ssh_set_error(sftp->session,
"%zu and asked for %" PRIu32, SSH_FATAL,
ssh_string_len(datastring), size); "Received a too big DATA packet from sftp server: "
"%zu and asked for %" PRIu32,
ssh_string_len(datastring),
size);
SSH_STRING_FREE(datastring);
return SSH_ERROR;
}
len = ssh_string_len(datastring);
/* Update the offset with the correct value */
file->offset = file->offset - (size - len);
memcpy(data, ssh_string_data(datastring), len);
SSH_STRING_FREE(datastring); SSH_STRING_FREE(datastring);
return (int)len;
default:
ssh_set_error(sftp->session,
SSH_FATAL,
"Received message %d during read!",
msg->packet_type);
sftp_message_free(msg);
sftp_set_error(sftp, SSH_FX_BAD_MESSAGE);
return SSH_ERROR; return SSH_ERROR;
} }
len = ssh_string_len(datastring);
/* Update the offset with the correct value */
file->offset = file->offset - (size - len);
memcpy(data, ssh_string_data(datastring), len);
SSH_STRING_FREE(datastring);
return (int)len;
default:
ssh_set_error(sftp->session,SSH_FATAL,"Received message %d during read!",msg->packet_type);
sftp_message_free(msg);
sftp_set_error(sftp, SSH_FX_BAD_MESSAGE);
return SSH_ERROR;
}
return SSH_ERROR; return SSH_ERROR;
} }
ssize_t sftp_write(sftp_file file, const void *buf, size_t count) { ssize_t
sftp_session sftp; sftp_write(sftp_file file, const void *buf, size_t count)
sftp_message msg = NULL; {
sftp_status_message status; sftp_session sftp = NULL;
ssh_buffer buffer; sftp_message msg = NULL;
uint32_t id; sftp_status_message status;
ssize_t len; ssh_buffer buffer = NULL;
size_t packetlen; uint32_t id;
int rc; ssize_t len;
size_t packetlen;
int rc;
if (file == NULL) { if (file == NULL) {
return -1;
}
sftp = file->sftp;
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(sftp->session);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
id = sftp_get_new_id(file->sftp);
/*
* limit the writes to the maximum specified in Section 3 of
* https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-02
* or to the values provided by the limits@openssh.com extension.
*
* TODO: We should iterate over the blocks rather than writing less than
* requested to provide less surprises to the calling applications.
*/
if (count > sftp->limits->max_write_length) {
if (sftp->limits->max_write_length > SIZE_MAX) {
return SSH_ERROR;
}
count = (size_t)sftp->limits->max_write_length;
}
rc = ssh_buffer_pack(buffer,
"dSqdP",
id,
file->handle,
file->offset,
count, /* len of datastring */
(size_t)count, buf);
if (rc != SSH_OK){
ssh_set_error_oom(sftp->session);
SSH_BUFFER_FREE(buffer);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
len = sftp_packet_write(file->sftp, SSH_FXP_WRITE, buffer);
packetlen=ssh_buffer_get_len(buffer);
SSH_BUFFER_FREE(buffer);
if (len < 0) {
return -1;
} else if ((size_t)len != packetlen) {
SSH_LOG(SSH_LOG_PACKET,
"Could not write as much data as expected");
}
/* Wait for the response in blocking mode */
rc = sftp_recv_response_msg(sftp, id, true, &msg);
if (rc != SSH_OK) {
return -1;
}
switch (msg->packet_type) {
case SSH_FXP_STATUS:
status = parse_status_msg(msg);
sftp_message_free(msg);
if (status == NULL) {
return -1; return -1;
} }
sftp_set_error(sftp, status->status); sftp = file->sftp;
switch (status->status) {
buffer = ssh_buffer_new();
if (buffer == NULL) {
ssh_set_error_oom(sftp->session);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
id = sftp_get_new_id(file->sftp);
/*
* limit the writes to the maximum specified in Section 3 of
* https://datatracker.ietf.org/doc/html/draft-ietf-secsh-filexfer-02
* or to the values provided by the limits@openssh.com extension.
*
* TODO: We should iterate over the blocks rather than writing less than
* requested to provide less surprises to the calling applications.
*/
if (count > sftp->limits->max_write_length) {
if (sftp->limits->max_write_length > SIZE_MAX) {
return SSH_ERROR;
}
count = (size_t)sftp->limits->max_write_length;
}
rc = ssh_buffer_pack(buffer,
"dSqdP",
id,
file->handle,
file->offset,
count, /* len of datastring */
(size_t)count, buf);
if (rc != SSH_OK) {
ssh_set_error_oom(sftp->session);
SSH_BUFFER_FREE(buffer);
sftp_set_error(sftp, SSH_FX_FAILURE);
return -1;
}
len = sftp_packet_write(file->sftp, SSH_FXP_WRITE, buffer);
packetlen = ssh_buffer_get_len(buffer);
SSH_BUFFER_FREE(buffer);
if (len < 0) {
return -1;
} else if ((size_t)len != packetlen) {
SSH_LOG(SSH_LOG_PACKET, "Could not write as much data as expected");
}
/* Wait for the response in blocking mode */
rc = sftp_recv_response_msg(sftp, id, true, &msg);
if (rc != SSH_OK) {
return -1;
}
switch (msg->packet_type) {
case SSH_FXP_STATUS:
status = parse_status_msg(msg);
sftp_message_free(msg);
if (status == NULL) {
return -1;
}
sftp_set_error(sftp, status->status);
switch (status->status) {
case SSH_FX_OK: case SSH_FX_OK:
file->offset += count; file->offset += count;
status_msg_free(status); status_msg_free(status);
return count; return count;
default: default:
break; break;
} }
ssh_set_error(sftp->session, SSH_REQUEST_DENIED, ssh_set_error(sftp->session,
"SFTP server: %s", status->errormsg); SSH_REQUEST_DENIED,
file->offset += count; "SFTP server: %s",
status_msg_free(status); status->errormsg);
return -1; file->offset += count;
status_msg_free(status);
return -1;
default: default:
ssh_set_error(sftp->session, SSH_FATAL, ssh_set_error(sftp->session,
"Received message %d during write!", msg->packet_type); SSH_FATAL,
sftp_message_free(msg); "Received message %d during write!",
sftp_set_error(sftp, SSH_FX_BAD_MESSAGE); msg->packet_type);
return -1; sftp_message_free(msg);
} sftp_set_error(sftp, SSH_FX_BAD_MESSAGE);
return -1;
}
return -1; /* not reached */ return -1; /* not reached */
} }
/* Seek to a specific location in a file. */ /* Seek to a specific location in a file. */
int sftp_seek(sftp_file file, uint32_t new_offset) { int
if (file == NULL) { sftp_seek(sftp_file file, uint32_t new_offset)
return -1; {
} if (file == NULL) {
return -1;
}
file->offset = new_offset; file->offset = new_offset;
file->eof = 0; file->eof = 0;
return 0; return 0;
} }
int sftp_seek64(sftp_file file, uint64_t new_offset) { int
if (file == NULL) { sftp_seek64(sftp_file file, uint64_t new_offset)
return -1; {
} if (file == NULL) {
return -1;
}
file->offset = new_offset; file->offset = new_offset;
file->eof = 0; file->eof = 0;
return 0; return 0;
} }
/* Report current byte position in file. */ /* Report current byte position in file. */